i know not a lot of these are out there yet in all areas,we have sold a few up here.my question is to the guys that do have them,what are you seeing for milage?just wondering if its varrying widely like past models

i know not a lot of these are out there yet in all areas,we have sold a few up here.my question is to the guys that do have them,what are you seeing for milage?just wondering if its varrying widely like past models
My DIC is showing 15.2. Mostly running around town miles

14.8 calculated on a 150 mile run yesterday. Less than 500 miles on the truck.
Ran about 70 mph on highway and about 15 miles at less than 30 mph.

thanks guys,i have one here stateing only 10 or 11 mpg,no sure how hes using it

I haven't seen a HD w/ the LMM engine yet here in Louisiana. Have seen a couple of base models w/ 6.0 gasser. But do want to drive one before I make decision on a new truck. Have driven the 08 fords which are very nice. Also have heard the mileage has put a beating on these trucks too.

I've put about 750 miles so fare and the trip computer is saying I'm getting 14.7 mpg. When I drove it off the lot with 35 miles on the odometer it read 11 mpg and it's been getting ever since. This has been mostly city driving. I haven't towed anything yet. About every time I drive it to work and back it improves another .1 mpg. We'll see where it stops. I think it'll be around 15-16 mpg city.

I filled up my LMM tonight and then drove 148 miles. 90% highway and about 10% stop/go and ideling in town. DIC said 17.5 MPG. I put in 8.5 gallons (filled it to the rim both times). Hand calculated 17.4 MPG. Highway speeds were between 65 and 75. Currently have 174 miles on the odometer.

Tom

I haven't figured out yet how to extract the MPG from the DIC, but I took mine on a trip today that I've previously taken with my '05 6.0L gasser, and I came home with a lot more fuel left over than I ever did with my gasser, which got 15 MPG. So I'm guessing I must have been in the 17-18 range atleast. I got my LMM with 320 miles on it, and now it has about 800.

Here is some info on my diesel mpg with a GMC Sierra 2500HD (GMC's Silverado). Hope it helps.

1,126 miles on new body style 2007 GMC Sierra 2500HD, Duramax/Allision, CC, Long body...

First fill up, combinations two laner, highway & 4WD, 16.35 mpg hand calculated. Second fillup, highway, two lane & 4WD, but primarily highway and New England mountains/hills 15.38 mpg. Third fill up combination highway & local, but primarily highway & fewer mountains/hills 18.4 mpg. All mileage hand calculated. DIC on most recent fill up indicated 18.8 mpg. Pretty close... my guess is that the discrepancy is due primarily to inability to really top off accurately & consistently each time. DIC indicated 20 mpg purely highway. I believe that is probably pretty accurate. Sweet spot seems to be between 68 mph & 72 mph.

Update at around 1,470 miles. Most recent tank fillup, 16.9mpg per DIC, haven't hand calculated yet, split nearly exactly half highway, half around town.

Although I am new to diesels, concerns about diesel particulate filter (dpf) in new LMMs appear to be overblown. This Duramax diesel 2500HD gets better fuel mileage than either of my two 1500 Suburbans.

I haven't figured out yet how to extract the MPG from the DIC, but I took mine on a trip today that I've previously taken with my '05 6.0L gasser, and I came home with a lot more fuel left over than I ever did with my gasser, which got 15 MPG. So I'm guessing I must have been in the 17-18 range atleast. I got my LMM with 320 miles on it, and now it has about 800.
320 miles:eek: did you get it as used:D :D

320 miles:eek: did you get it as used:D :D

I had it transfered from out of state actually. Hey dieseljoe which stations do you usually fuel up at? I'll be going back and forth between SJ and Riverside.

Hi Guys Im new here and I just bought my first diesel truck.
The new Silverado Duramax LMM. I'll try and post some pics from when I picked it up on 4/03/07. so far on a new motor im averaging 16-17 mpg. with average type driving.

Hi Guys Im new here and I just bought my first diesel truck.
The new Silverado Duramax LMM. I'll try and post some pics from when I picked it up on 4/03/07. so far on a new motor im averaging 16-17 mpg. with average type driving.

Looks great! That's a great color too. Awesome mileage for an engine not even broken in yet :)

Hi Guys Im new here and I just bought my first diesel truck.
The new Silverado Duramax LMM. I'll try and post some pics from when I picked it up on 4/03/07. so far on a new motor im averaging 16-17 mpg. with average type driving.

Nice looking truck !!

I just picked mine yesterday. I test drove it wih 1.2 miles on it. Hooked up my boat to it with 7 mile on it. Drove it 300 miles last night and got only 8.9 MPG. I hope this thing gets ALOT better. I will definetly need a larger fuel tank. I am used to my 3500 dually and the massive tank. I filled up 3 times already.

A pic

Looks great! That's a great color too. Awesome mileage for an engine not even broken in yet :)


I agree Roadshark. That truck does look great and that MPG is really good for a new diesel...
So far, it seems like LMM Fuel mialage is very very similar to LBZ mialge based on what you guys are saying about your LMM trucks.

Once broken in, the LMM should get 20+ on good days crusing down the highway from what some LBZ guys have said...What do you guys think?

A pic


The New Duramax looks Great 4HUN. Especially while towing a boat! :D

Do you do alot of fishing, wakeboarding, and waterskiing 4HUN? I love that type of stuff...when I get my LMM, Im definately going be be looking through boat trader on a weekly basis...;)

We wakeboard about twice a week. The truck will lifted with 22's in the next couple of weeks. Ill be sure to post pics. I still think my dually looked better towing my boat. I am kind of disappointed. Hopefully with the wheels it will look better!!

Hey guys, I've got about 1475 miles my LMM right now. I picked it up about 3 weeks ago. The first few hundred miles were 10-12. After 500 miles it went to about 12-13. Currently, I'm getting 14-16 depending on the driving condition. I drive mainly to and from work, 65 miles combined, through city streets. I also have to say that on the freeways I was getting 19-21 through 100-120 mile stretches. I'm completely satisfied with this motor thus far in the break-in stages.

My buddy just bought a LMM he had a 6.0 gas he figuerd he would get better milage he calls me all scared because he's only getting 13.0 by hand truck only has 1500 miles i told him to relax it's still breaking in i said give til about 5k. By the way i drove it and all i can say is the drivetrain is very smoooth but as far as the leather seats there not to comfy. dave

My DIC is showing 15.2. Mostly running around town miles

My truck is only about a week or so old have burnt only about 50 gal of fuel so far and my dic refuses to show over 10.6 MPG!! WTF I get on it once in awhile but its not like im runnoing wide open all the time....

My truck is only about a week or so old have burnt only about 50 gal of fuel so far and my dic refuses to show over 10.6 MPG!! WTF I get on it once in awhile but its not like im runnoing wide open all the time....

The MPG seems to be all over the place. One person has 19. The next has 14, and yours is 10.6. What is up with this? It would seem that it should be the same cross the board, or close anyway.

Jim

The MPG seems to be all over the place. One person has 19. The next has 14, and yours is 10.6. What is up with this? It would seem that it should be the same cross the board, or close anyway.

Jim

i bet it has to do with how they drive and where they are and the set up. And the lb7s llys and lbzs all have varing milage within each. but if the stock lmm is capable of getting 19 on some occations that is not bad with all that $#!^ in the exhaust

Get vehicle warmed up, drive down the highway at a reasonable speed, then reset the DIC and watch it's performance. If you are still getting 10.6 then you have some issues. If you are getting 16+, you are fine. On diesel trucks, unless DIC is reset, you will have a total average mpg, which includes idling, spinning tires to impress someone, checking out how fast you do the quarter mile etc. I would try this, also you have to include something for break-in period.

I test drove the one that I bought yesterday for 30 miles after erasing the Dic, and I drove it very gently to see what it would get. When I pulled it back on the lot it said 18.6 on the DIC. The sales lady was very impressed because she had been telling customers to expect 12-13. The truck had 39 miles on it when I bought it and it was a LMM/

Jim

I test drove the one that I bought yesterday for 30 miles after erasing the Dic, and I drove it very gently to see what it would get. When I pulled it back on the lot it said 18.6 on the DIC. The sales lady was very impressed because she had been telling customers to expect 12-13. The truck had 39 miles on it when I bought it and it was a LMM/

Jim

This is nice to know. When mine finally arrives I can do my own testing.

Jim

It's the same whether, gas, diesel, lb7 or lmm. If you drive like a lunatic you'll get low mileage. If you drive with a light right foot you'll do better.

I can romp on my lly and get 12mpg, or p*ssy foot it and get 19 highway (at 60mph though).

-Chris

I would agree with the comment of resetting DIC while driving highway and see what happens.

How do you access the MPG display? The dealer is mailing my the owners manual, but in the meantime I've been trying to figure that out because I'm dying to know, and be able to see it change as it breaks in. I tried the little button on the right side of the dash but it only cycles between the odometer and a trip counter.

RoadShark... others may chime in, but if you don't have steering wheel controls you may be SOL on the mileage and other features of the DIC. I'm pretty sure on the gmt800's the DIC (which gives mileage as well as other features) is an option.

-Chris

RoadShark, I believe you have this option.. I mean, don't they all? You should have four buttons on the right side of your driver-side dash. You'll find that when you cycle through the very top button it does go through trip and such. Your MPG is located within there. I'm sure you're passing it up though. When you are able to locate it, you just hold the check-mark which is the last button of the 4, and it will reset. Let me know if you can't find it and I'll take some pictures for you.

Thanks Chorethorious. Are the buttons outside the instrument cluster on the right? I think there's some buttons there I'll go out and check. The one I've tried so far is the little tiny knob type button that's inside the instrument panal squeezed between the gages on the right. I do have steering wheel buttons too.

They aren't in the cluster, but actually on the dash, next to the vent. You'll find them in a vertical position. Just press the very top one to cycle through things, such as trans temp, milage remaining, fuel used and so on. You will also be able to setup controls through the 3rd button from the top, such as seating position reminder, volume adjustment and so on.

Does your guys truck stay running even though the key is off until you open the door does it shut off?

The electronics stay on. This feature is only set on the driver door. The passenger door can open and not turn off the electronics. Keep in mind that this should turn off after 10 minutes if the door is not opened.

Just wondering, I pulled the Gmc up to my front door, shut the key off and it kept running, I was like huh thats weird.

That is very odd. I can understand the remote start, but after the ignition is turned to the off position, wow. I'm curious if you would have been able to put it in gear. Well, I've yet to see anything funky like that. Although my wipers and cleaner did start going for no reason. That almost made me believe I had rainsensing wipers. haha

I'm not sure on the new GM remote start, but on the Command Start that I have you can activate the remote start when the vehicle is running. You can then turn off the ignition and remove keys and vehicle will run for 15 minutes. Perhaps if GM has the same option, you accidently activated the command start feature prior to turning off the vehicle.

Hmm That could very well be. I've yet to hear about it, but that doesn't mean it isn't there. We are all learning about these vehicles from each others experiences.

One other thing that I forgot to mention, with this option when you touch the brake pedal ( you need to do that to shift) this shuts down the engine. So you could not drive away without the ignition keys. In Canada we use this feature a lot to keep vehicle warm while we are out of vehicle at Post office, store etc, but still keeps it from being stolen with the keys in the ignition.

Are you speaking about a Honda or a GM? If a GM, please explain if this if you have to hit a button or what not. Cause I didn't see anything like this in my manual or other paperwork. I have even thought about keeping multiple keys on me for this very reason. Very dangerous I know, but also a way around having to turn on and off the truck at times.

Are you speaking about a Honda or a GM? If a GM, please explain if this if you have to hit a button or what not. Cause I didn't see anything like this in my manual or other paperwork. I have even thought about keeping multiple keys on me for this very reason. Very dangerous I know, but also a way around having to turn on and off the truck at times.
When the truck is running touch the auto-start button then take the key out of the ignition, don't touch the brakes and get out, the truck will stay running.

OH!!! I didn't even think about the key fob. Thanks Dave!

Very interesting & informative discussion. So the remote start must be that top button on the key fob I've been afraid to press because I don't know what it does, the one with an arrow going in a circle? :)

Very interesting & informative discussion. So the remote start must be that top button on the key fob I've been afraid to press because I don't know what it does, the one with an arrow going in a circle? :)Yes that's the one the only problem with the GM starter it doesn't let you know the truck is running so i had to listen for the truck to start and it doesn't have much range. dave

Ok Ok.. I must be a tard, because I was unable to get this "stay going" option to work. I was in the truck.. it was running.. I pressed the remote start on the fob.. turned the key back to pull it out and the engine went off. I even went so far as to try it again and this time I held the remote start button for about 5 seconds. No go with that either.. I'm starting to think this is a myth... as no one else has confirmed this. Anyone?

BTW, Roadshark, in order to use the remote start you must first press the door lock and then press and hold that remote start button. It takes about 5 seconds and you will hear the engine kick over. The engine will stay going for 10 minutes, and I believe you can do this twice. After the 2nd time it turns off you will need to actually go and start it with the key.

My truck is only about a week or so old have burnt only about 50 gal of fuel so far and my dic refuses to show over 10.6 MPG!! WTF I get on it once in awhile but its not like im runnoing wide open all the time....

I must admit you guys have brought up some good points. I will reset the DIC and let you know what happens. Also another variable could be I put on 285's and the truck came with 265's. This canb affect milage over a stock dmax. after mopre thought I relized another thing working against me could be I never adjusted the speedo so I may be getting inaccurate distance readings.

Ok Ok.. I must be a tard, because I was unable to get this "stay going" option to work. I was in the truck.. it was running.. I pressed the remote start on the fob.. turned the key back to pull it out and the engine went off. I even went so far as to try it again and this time I held the remote start button for about 5 seconds. No go with that either.. I'm starting to think this is a myth... as no one else has confirmed this. Anyone?

BTW, Roadshark, in order to use the remote start you must first press the door lock and then press and hold that remote start button. It takes about 5 seconds and you will hear the engine kick over. The engine will stay going for 10 minutes, and I believe you can do this twice. After the 2nd time it turns off you will need to actually go and start it with the key.

Thanks Chorethorious. I found the button on the dash to display MPG, and just as you said, it was the top button of three. Only on mine it was on the left side of the dash, probably because I have the standard dash. Anyway thanks for clueing me in. My running avg is 18.5 MPG. I guess that includes all driving since it's never been reset (another thing I don't know how to do yet :) ).

WOW!!! 18.5... teach me how to drive!! You are correct though, that is a cumulative average of your total milage. Since you've not restarted it once it is showing from mile 1, give or take. Congrats! BTW, your welcome. I didn't realize that the configuration was different. Good to know :)

I'm not sure on the new GM remote start, but on the Command Start that I have you can activate the remote start when the vehicle is running. You can then turn off the ignition and remove keys and vehicle will run for 15 minutes. Perhaps if GM has the same option, you accidently activated the command start feature prior to turning off the vehicle.


My remote start in my other truck is the same way. I haven't used the new truck enough to see if it does the same thing. That would come in handy!

LOL :) Well, I do mostly highway driving back and forth to work, about 50 miles/day, and that also includes a trip to AZ and back. I should be getting my manual this week, but how do you reset the MPG counter?

WOW!!! 18.5... teach me how to drive!! You are correct though, that is a cumulative average of your total milage. Since you've not restarted it once it is showing from mile 1, give or take. Congrats! BTW, your welcome. I didn't realize that the configuration was different. Good to know :)

When you have the MPG selected, you push and hold the 4th button down *Check Mark.* This will reset the metric for this. Keep in mind that this works for the trip and other metrics as well. All except odometer.. haha

Im upto 12.7 now and climbing....truck is still breaking in

I want a new Duramax! Unfortunately at 24 and two kids and struggling business I can not afford new truck. Hopefully with some home based business stuff I am just starting (with success so far) I will be able to buy new (well at least 3-4 years at oldest) pickup. Only time will tell.

DuraMaxxed - Are you towing and getting that or empty? I'm at 2k miles now and getting 16.4ish mpg combined on a tank. I do both spirited driving as well as SOME conservative. I'm just curious if you're driving habits are a little too aggressive or something else.

Side note - Anyone else have issues with these small fuel cells? I feel like I only have a 20 gallon tank. The fuel meter is reading E and I flip to how much fuel I've used and its on 19-21.. What gives?

Ive got a new duramax I have 2200 miles on it now, I haven't towed anything yet with it but im getting 15.4 miles to the gallon. I dont do all highway driving some but mostly off highway miles. I drive it pretty hard so im happy with it so far.

12.7 and climbing here too = ]

When you have the MPG selected, you push and hold the 4th button down *Check Mark.* This will reset the metric for this. Keep in mind that this works for the trip and other metrics as well. All except odometer.. haha

Thanks! I still don't have my manual, the dealer screwed up again - they sent me a Sierra "Classic" manual for the old style trucks! Completely useless to me. Should have known they couldn't even get that right. It says Classic right on the cover.

Thanks! I still don't have my manual, the dealer screwed up again - they sent me a Sierra "Classic" manual for the old style trucks! Completely useless to me. Should have known they couldn't even get that right. It says Classic right on the cover.

Just talked to the dealer and he's going to send the right manual tomorrow, so maybe, if nothin else goes wrong, I'll finally have a manual for this truck by Monday or Tuesday. In the meantime, Chorethorious or anyone else with the camper mirrors, can you tell me how to adjust them? I'm assuming they're adjustable from the inside. I keep loosing cars in that split mirror and I think I just need to adjust them better. Thanks (again)! :)

NP, the circle on the driver side door is how you'll change the top portion of your camper mirror. Below the circle is a toggle switch that you must press right or left, that is how you'll pick your mirror. You will know you have a mirror selected when you see an amber LED on the side you selected. You turn that off by pressing it again. From there you just go to town moving the mirror to your preference.

**A side note ** I love the Ford mirrors because you can actually extend and fold the camper mirrors from inside. As the GM you'll have to get out and move them in or out and fold them.

NP, the circle on the driver side door is how you'll change the top portion of your camper mirror. Below the circle is a toggle switch that you must press right or left, that is how you'll pick your mirror. You will know you have a mirror selected when you see an amber LED on the side you selected. You turn that off by pressing it again. From there you just go to town moving the mirror to your preference.

**A side note ** I love the Ford mirrors because you can actually extend and fold the camper mirrors from inside. As the GM you'll have to get out and move them in or out and fold them.

Now I understand, thanks. Looks like the lower one has to be adjusted from the outside though. I don't know, I might just get these mirrors swapped for some below-eye-level mirrors. I'm finding these ones are just a little too big, and block my view in a lot of situations, and I already clipped the side mirror of an F250 in a tight, crowded service station the other day (luckly the F250 had fold away mirrors so there was no damage).

Got mine yesterday and already have 121 miles on it. I reset the fuel calculator after the first 40 miles and it is giving an average of 14.9 MPG. Still too early in the game to make a call...

GMTom, it really is, but expect some pretty decent fuel economy for a big diesel!

Hey Chorethorious, I just had a new high avg mileage today..... 20.8 MPG!!
Starting out in stop and go traffic before getting on the freeway today it showed 14.5 MPG, but it steadly climbed while on the freeway mostly at 65-70 MPH, but sometimes at 75 and 60. I finally reached 20.8 MPG at the end of a 50 mile trip almost all of it above 60 MPH. Total mileage now is about 1,700 miles.

That is some awesome milage. I am really pleased with the milage I'm getting in city traffic, which is about 16-16.5 now. Once I get it 'broke-in' I will swap back to my car. Even though that gets about the same milage, but my foot never leaves the floor in that car, lol.

RoadShark, how many miles a month do/will you put on your LMM? I probably average about 1500 right now, but don't want to neglect other vehicles. Anyway, congrats and stellar milage!

That is some awesome milage. I am really pleased with the milage I'm getting in city traffic, which is about 16-16.5 now. Once I get it 'broke-in' I will swap back to my car. Even though that gets about the same milage, but my foot never leaves the floor in that car, lol.

RoadShark, how many miles a month do/will you put on your LMM? I probably average about 1500 right now, but don't want to neglect other vehicles. Anyway, congrats and stellar milage!

Thanks Chorethorious. So what other vehicles do you have? I drive about 800 miles/month, but I'm in the process of moving now, with many 50 mile trips (100 both ways) back and forth. Then after I'm moved I'll be slightly further away from work. I noticed in another post you said you live near Phoenix? I drive out to Scottsdale every so often, really nice roads out there, especially that 101 loop. Must be nice to not have to maintain a lawn at your house. :) I like the natural look with cactus, unfortunately the natural look out here is weeds :D

I have an 04 bmw 545/ 96 nissan pickup/ 05 scion xb <--- Wifes. I really enjoy the 545 though, 0-60 5.2ish.

I'm out on the west side of "Phoenix." I hate the loop during traffic, but it is a nice ride when you can drive it. The lawn part is a big plus though. I only have to maintain some trees and plants.. no mowing. Although I have 4 dogs, 2 rotties and 2 ****ers, which I need to plant grass in the back for. In due time.. due time.

Picked up my LMM C.C. today and found I got 20+ mpg (American gallon) (24+ on the Canadian gallon)on the highway if I kept it at around 60 mph on level prairie, slight crosswind. Less than 100 miles on vehicle, so it looks promising. This was from reading DIC, have not driven enough to do actual calculation. I drive with a light foot and consistently got 24+ Canadian with my 03 1500 gas.

Wow, that is awesome cookkey! I filled up again last night, ~2500 miles, and got 18.2 through traffic on my way home. I have a ~40 mile drive home from work. I'm only looking up when it comes to the gas milage of this vehicle. I'm not surprised about the awesome milage, but I also budgeted for the worse. I planned to get about 10-12 miles to the gallon for the first few months. I'm just trying to get up to Radioshark's numbers :lol:

I have about 3500 miles on mine and have not seen over 16. I hope it gets better as she breaks in. My 04' wa sgetting 22 all day long!

New to the forum. We just picked up our first diesel. 3500 Crew Longbed single rear z71. So far AVG on dash shows 16.8. Only 200miles or so driving mostly hwy at +75. Lots of power, looking forward to mpg in the 20s.

Well I filled the truck up the other day and the amount consumed and the amount I filled were right on, so my DIC is accurate in using for a guide as to fuel mileage. Did a 200 mile trip today with a couple of stops and average 20.9 American on the way up and 21.5 mpg (American on the way back) Driving at 60 -65 mph. Truck is now officially broken in and look forward to seeing mileage towing. It has already surpassed my gas vehicle, and my expectations, my gaser only got 18 mpg when I first got it and it moved up to the 21 -22 mpg range after about 12,000 miles.

I just did a 20 mile highway run just for curiousity...
I have 286km...177 miles on my new truck

Keep the speed at 65mph.....and reset the DIC...

The Dic settled in at 11.5liters/100km....which translates to 23 miles to the Canadian Gallon..

or, 20.46 miles to the American gallon.

Wow, that is awesome cookkey! I filled up again last night, ~2500 miles, and got 18.2 through traffic on my way home. I have a ~40 mile drive home from work. I'm only looking up when it comes to the gas milage of this vehicle. I'm not surprised about the awesome milage, but I also budgeted for the worse. I planned to get about 10-12 miles to the gallon for the first few months. I'm just trying to get up to Radioshark's numbers :lol:

Hey Chorethorious how's your mileage doin now? :) Finally got my manual, also got my plates the same day! Went out today to put them on - I got the rear plate on, it only had two screws to hold it on though, I'll have to get two more. And I don't know why I bothered putting the stupid plastic dealer lic plate frame back on, it covers up too much of the plate. Anyway, I then moved on to the front - and WTF??? There's no place to put it! No front dealer paper plate, or lic plate frame. Nothing. I hadn't noticed that before for some reason. But am I missing something, or are there some holes there somewhere in the front bumper (& hopefully w/ screws)? Did you get yours on yet?

this is like a conversation that i heard at the mall yesterday( two fat ladys were telling the store clerk that they weight 145 lb and to me they look way over 180 lb) sometimes you have to lie to reasure yourself and get you selfconfidence back, on my lbz i could tell you that i'm getting 26 mpg but in reality i'm getting 15.8 mpg. it is perfectly normal to get veriance numbers even with indentical vehicles, it all depends on location,how well maintain. tires,quality of fuel,wind,but some of you seem to forget the big reason( the DRIVER.)

this is like a conversation that i heard at the mall yesterday( two fat ladys were telling the store clerk that they weight 145 lb and to me they look way over 180 lb) sometimes you have to lie to reasure yourself and get you selfconfidence back, on my lbz i could tell you that i'm getting 26 mpg but in reality i'm getting 15.8 mpg. it is perfectly normal to get veriance numbers even with indentical vehicles, it all depends on location,how well maintain. tires,quality of fuel,wind,but some of you seem to forget the big reason( the DRIVER.)

I don't know who you're responding to but the numbers I posted come straight from the DIC.

Hey Chorethorious how's your mileage doin now? :) Finally got my manual, also got my plates the same day! Went out today to put them on - I got the rear plate on, it only had two screws to hold it on though, I'll have to get two more. And I don't know why I bothered putting the stupid plastic dealer lic plate frame back on, it covers up too much of the plate. Anyway, I then moved on to the front - and WTF??? There's no place to put it! No front dealer paper plate, or lic plate frame. Nothing. I hadn't noticed that before for some reason. But am I missing something, or are there some holes there somewhere in the front bumper (& hopefully w/ screws)? Did you get yours on yet?

front licence plate braket is an option.

Just did my first fillup...Truck has 432 km or 268 miles....
Combined city/hwy driving...truck unloaded

It took 61.91 liters to fill which is 13.62 Imperial gallons
That translates to an average of...19.67 MPG Imperial

61.91 liters is 16.09 U.S. gallons
That translates to.......16.65 MPG U.S.

finally had a chance to fill both tanks and verify DIC. DIC is higher than my calculated mileage. My LMM has over 2500 miles now.
1111 mile trip, mostly highway at 65-80 mph calculated 17.6mpg.
My last 306 miles, mixed in town and highway calculated 16.3.
The highway mpg is about 2 less than my 2003 LB7 and the miexed is about 1 less. So far I'm happy.
PJ

finally had a chance to fill both tanks and verify DIC. DIC is higher than my calculated mileage. My LMM has over 2500 miles now.
1111 mile trip, mostly highway at 65-80 mph calculated 17.6mpg.
My last 306 miles, mixed in town and highway calculated 16.3.
The highway mpg is about 2 less than my 2003 LB7 and the miexed is about 1 less. So far I'm happy.
PJ

Both tanks? Do you have an aftermarket aux tank, pjappraiser? If so, which one? I've been waiting on TransferFlow to release one for the new trucks.

Well, the plate thing up front threw me.. but I really like the look without the holes in the bumper. I took the dealer plate off at the lot. I just threw the temp plate on a cardboard strip and sat it in the back window. I went and bought a GMC plate where my license plate would go. A few people thought it was pretty interesting.

Anyway, to the guy possibly saying that people aren't being real about their numbers... Who knows? I could go to the extent of actually taking photos of my DIC, but I don't care enough for you to believe me or not. In reference to the tires and lift and driving style and.. and.. you couldn't be farther from the truth. That should be plain logic though.

Anyway, I'm getting a stable 17 MPG now commuting to and from work. Currently I have ~3K mile on the truck. I'm just trying to get to around 10K so that I can swap out the oil with synthetic. But, the MPG did decrease GREATLY, down to 12-13 MPG with the same driving style this past week. I wasn't sure if it was the fuel, most likely not, or the REGEN. Which there is already a topic on this elsewhere.

Anyway, congrats on FINALLY getting your manual. I hope it really helps with understanding a few more features of your truck.

BTW, I'm heading to Riverside/Corona this weekend. I hope the weather is nice.

Road Shark, I have a 51 gal. aux tank/tool box from Northern with their gravity feed install kit. Works good! I try to fill both the day after my credit card bills. Since fuel seems to be going up during the month. Gives me a month before I have to pay.
PJ

pjappraiser,

Wow!! so you carry just over 75 gal. after fill-up? I find that I go about 20 gal. a week'ish right now. Can you shoot me some info on the aux tank?

Nice setup btw.

i wonder how the new dually will fair with MPG and lmm. the past 2500 hd,s always seem to get 2 or 3s mile better per gallon than the dually. and from what i see with your new trucks 2500hd it look like the dually might be around 13-15 mpg if this stand true to the past numbers. not good..

Come on.. you cannot make an assessment such as that. ESPECIALLY since these vehicles have only been on the market for 2 months. Do you think these trucks would be getting 21 MPG out of the gate? If so, let me know what your smoking, cause I might want some.

http://www.dieselplace.com/forum/showthread.php?t=153872 This is a discussion in the LBZ area regarding fuel MPG. Seems they are also running through the same issue with new motors. I fall back on my statement of both this vehicle is new and that you cannot gauge where MPG are going to be from people who all have under 10K... 60K miles for that matter.

New to the forum. We just picked up our first diesel. 3500 Crew Longbed single rear z71. So far AVG on dash shows 16.8. Only 200miles or so driving mostly hwy at +75. Lots of power, looking forward to mpg in the 20s.

How about some photos of your 3500 SRW !! :ro)

Just did my first tank, and the mpg around 16. Highway and city about even. Oh, this is a 1 ton SRW also.

man oh man chorethorious, Im not sure how many diesels you have had, and no need to get all defensive, but after 5 duallys I have a very good idea of what the dually might do. as well as many people that I know with the 2500 hd always gets bettter MPG than the dually. so sorry for making statement or a thought you didnt like. maybe you had some bad crack.!

Well, regarding the crack, possibly. With the dually, I've never owned one. But, your statement was aimed at the MPG that the LMM was getting. You stated that the dually will get 2 - 3 MPG less. Maybe, but you are basing your disappointment off very early run engines. I pointed out the LBZ primarily to show that its not the LMM, but mostly all new diesels getting 11-17 MPG. I honestly don't feel that is too bad. I wasn't getting defensive.. maybe a little, but come on, I really think these will perform just as well as other generations with regard to MPG. Time and miles will tell the story though. Anyway, have a good one and enjoy the weather!

Thanks Chorethorious, how does the lic plate mounting work upfront? I always thought the manufactures were required to provide a way to mount both front and back plates by law? So far I'm just carrying the front plate around in the cab, probably until my 1st oil change when I'll have the dealer put it on. Fraid I might get a ticket for having no front plate :)

I hope ya have a good trip out here, are you drivin? Weather should be good this weekend. We're having a little "June Gloom" right now - cool and cloudy mornings, sometimes with fog, maybe a little drizzle, and warm hazy afternoons in the 70's and 80's. If you come down the 215 from the 10, beware of being in the slow lane when you approach the 215/60/91 interchange because the slow lane turns into a connector to the 60 East. Lots of overpass construction going on in that area.

Well, the plate thing up front threw me.. but I really like the look without the holes in the bumper. I took the dealer plate off at the lot. I just threw the temp plate on a cardboard strip and sat it in the back window. I went and bought a GMC plate where my license plate would go. A few people thought it was pretty interesting.

Anyway, to the guy possibly saying that people aren't being real about their numbers... Who knows? I could go to the extent of actually taking photos of my DIC, but I don't care enough for you to believe me or not. In reference to the tires and lift and driving style and.. and.. you couldn't be farther from the truth. That should be plain logic though.

Anyway, I'm getting a stable 17 MPG now commuting to and from work. Currently I have ~3K mile on the truck. I'm just trying to get to around 10K so that I can swap out the oil with synthetic. But, the MPG did decrease GREATLY, down to 12-13 MPG with the same driving style this past week. I wasn't sure if it was the fuel, most likely not, or the REGEN. Which there is already a topic on this elsewhere.

Anyway, congrats on FINALLY getting your manual. I hope it really helps with understanding a few more features of your truck.

BTW, I'm heading to Riverside/Corona this weekend. I hope the weather is nice.

pjappraiser,

Wow!! so you carry just over 75 gal. after fill-up? I find that I go about 20 gal. a week'ish right now. Can you shoot me some info on the aux tank?

Nice setup btw.

X2! :)
With there not being as many diesel stations around as gas, I like the idea of being able to carry more fuel in between fillups, and not having to fillup as often.

Further update on mileage. As stated previously I was looking forward to my towing mileage. Today did a round trip towing trailer and averaged 12.5 mpg. It is a 7 x 14' Pace cargo trailer weighing an estimate 5,000 lbs. Trailer has an additional 6 inches of height from standard trailer and a little more wind resistance. Thought I would get closer to 14-15mpg. I also found it was better to travel in 5th rather than 6th gear. No shifting and the mileage seemed better. Strong windos today. Did not start using 5th till later in trip.
Later in the day an unloaded trip with heavy winds netted the following.
17.0 mpg heading into winds at 60 mph. Reset DIC for return trip and got 22.5 mpg with wind pushing cruising 65 mph. Average of trips 19.7 mpg.
All these are from the DIC. I have done several fills and the amount used from the DIC and the fill are identical within fractions. These trips are on open country roads with a few small hills. Driving in town, mileage is around the 10-12 mpg mark, stopping and starting frequently for numerous 4 way stops.

My 51 gal aux tank is from Northern, built by RDS. link below
http://www.northerntool.com/webapp/wcs/stores/servlet/NTESearch?storeId=6970&N=0&Ntk=All&Ntt=fuel%20tank&Nty=1&D=fuel%20tank&Ntx=mode+matchallpartial&Dx=mode+matchallpartial
It has a small, but usable 6" deep storage areas above the tank. They have several sizes. Mine is mounted in a short bed.
PJ

here is a shorter link to Nothern tanks
http://tinyurl.com/27apgw
PJ

Has anyone actually burned the amount of fuel or filled a tank to the spec's? I think the marketing/manual claims a CC reg box had a 26G tank. I use 75-80% of that and I'm almost on E... haven't had the low fuel light come on yet but I can't imagine the bottom end of the tank has that much left in it.

I thought I saw a thread on this earlier but couldn't find it.

15.7 through first 700 miles

I just picked mine yesterday. I test drove it wih 1.2 miles on it. Hooked up my boat to it with 7 mile on it. Drove it 300 miles last night and got only 8.9 MPG. I hope this thing gets ALOT better. I will definetly need a larger fuel tank. I am used to my 3500 dually and the massive tank. I filled up 3 times already.
I thought mine was bad, I am averaging 9.3mpg, granted I am running with 40's but 8.9, damn, with stock tires and wheels I hope it gets better!

Well, I returned to Cali a little earlier than expected. I got 17.1~ 350 miles one way, Phx - Riverside. The way back was slightly better @ 18.5. Going to Cali I was driving late morning with the tailgate up. Driving back to Phx it was the middle of the night with the tailgate up. Also, I was carrying about 80lbs worth of baggage and 270lbs worth of 2 dogs :)

Regarding the license plate cover, I believe they'll need to drill the holes in the front. I looked and didn't see any depressed areas for the holes, but hopefully the dealerships service department will know. Thankfully we only have a rear plate here in AZ. I was thought getting a few glances from cops as they drove past me in Cali.

BTW, I had the cruise set to 75MPH towards Cali, and 70 towards Phoenix

Further update on mileage. As stated previously I was looking forward to my towing mileage. Today did a round trip towing trailer and averaged 12.5 mpg. It is a 7 x 14' Pace cargo trailer weighing an estimate 5,000 lbs. Trailer has an additional 6 inches of height from standard trailer and a little more wind resistance. Thought I would get closer to 14-15mpg. I also found it was better to travel in 5th rather than 6th gear. No shifting and the mileage seemed better. Strong windos today. Did not start using 5th till later in trip.
Later in the day an unloaded trip with heavy winds netted the following.
17.0 mpg heading into winds at 60 mph. Reset DIC for return trip and got 22.5 mpg with wind pushing cruising 65 mph. Average of trips 19.7 mpg.
All these are from the DIC. I have done several fills and the amount used from the DIC and the fill are identical within fractions. These trips are on open country roads with a few small hills. Driving in town, mileage is around the 10-12 mpg mark, stopping and starting frequently for numerous 4 way stops.


I wouldn't expect any better mileage then what you are getting now. My thoughts on the matter of towing are as follows: Doesn't matter how much weight you tow within reason. What matters more is the frontal area of what you are towing. Reason being is Aerodynamic HP. In that equation no where can you find the factor "Weight" it is all about frontal area, speed and drag coefficient. Once you are up to speed it takes very little to maintain it but it takes a sufficient more amount of HP to for a larger frontal area, (trailer). Relating it to my road experiences I get the same MPG towing either my old 5K pound travel trailer vs. my 9K pound 5'er. The 5'er is maybe even better as since it sits in the bed of the truck it is a little bit more aerodynamic then the travel trailer. If I ever got 14 while towing then just tickle me and wake me up.

BTW, I had the cruise set to 75MPH towards Cali, and 70 towards Phoenix

You mean you didn't take advantage of the opportunity to go 80 (5 mph over the limit) between the state line and Avalondale? :D

Well, I returned to Cali a little earlier than expected. I got 17.1~ 350 miles one way, Phx - Riverside. The way back was slightly better @ 18.5. Going to Cali I was driving late morning with the tailgate up. Driving back to Phx it was the middle of the night with the tailgate up. Also, I was carrying about 80lbs worth of baggage and 270lbs worth of 2 dogs :)

Regarding the license plate cover, I believe they'll need to drill the holes in the front. I looked and didn't see any depressed areas for the holes, but hopefully the dealerships service department will know. Thankfully we only have a rear plate here in AZ. I was thought getting a few glances from cops as they drove past me in Cali.

That might explain it, since my truck started out as an AZ truck before a dealer transfer. I had it at the dealer today, they have to special order the mount. I had to have it towed in today, it died on me this morning and wouldn't start back up. Here's the gritty details: http://www.dieselplace.com/forum/showthread.php?goto=newpost&t=156112

Well, I wasn't in a big hurry and I thought that it might be better take my time driving. Also, the cops did play a role as there were a few here and there. The engine did its job as predicted. I was hoping for better fuel mileage, but was let down softly. Thankfully I was able to get each way on one tank, which made up the bad mileage for me.

I commented about the issues you had with your truck in the other thread. Either way, I'm still curious as to how the heck your filter was leaking. Far to early for the gaskets to blow out. Anyway, glad everything is back to normal for you :)

Got my LMM 3 weeks ago and went from Indiana to Florida and all over that state for 2 weeks. Put 3200 miles while on vacation there and averaged 18mpg running from 70 to 75mph. I would have to look at my GPS to see averages of the trip. Sure beats the 2500 Avalanche with the 8100 Vortec I had. It averaged about 12mpg. I loved that truck but I love the new truck.

Brian

Well, I wasn't in a big hurry and I thought that it might be better take my time driving. Also, the cops did play a role as there were a few here and there. The engine did its job as predicted. I was hoping for better fuel mileage, but was let down softly. Thankfully I was able to get each way on one tank, which made up the bad mileage for me.

I commented about the issues you had with your truck in the other thread. Either way, I'm still curious as to how the heck your filter was leaking. Far to early for the gaskets to blow out. Anyway, glad everything is back to normal for you :)

Your mileage isn't that bad actually considering it's still new, it's bound to get better. My avg mileage's been down lately, holding at 17.5 since the last fillup. Traffic's been a lot worse the last few weeks, lots of stop & go all the way to work and back. I haven't had a chance to hit 70 at all except for the last couple miles on the way home, and a brief stretch on the way to work before passing the 10. Plus I don't know if the fuel leak had any impact on what the DIC reported but now that it's fixed my actual mileage has to be better. They said it was the seal that was the source of the leak. I sure wish I knew why but I guess it was just bad luck that I ended up with a defective one.

Ok, I've heard that the DIC's mileage is pretty accurate, but I had my doubts today. I reset it this morning on the way to work, and it shoot way up to 40! It didn't last long, just seconds, & quickly dropped off to 30, and then stabilized at 25.6, which still seems bogus. Traffic was good - being a Sunday morning I was able to hold a steady 70 MPH. Once I got off the freeway the mileage dropped off to 23. On the way home traffic was a bit heavier, and when I got home, the DIC was reading an avg of 20.3. Anybody else see wild readings like that? Is it possible to have brief periods of super high mileage numbers, which avg out in the long run? 25.6 MPG sure looked good on my dash while it lasted. :)

not out of the ordinary to see that. my 05 and 06 dic will do the same. on my o5 i have seen it to 56mpg i resest it going down a very long grade with the trailer behind me. eventually it corrects itself.

Ok, I've heard that the DIC's mileage is pretty accurate, but I had my doubts today. I reset it this morning on the way to work, and it shoot way up to 40! It didn't last long, just seconds, & quickly dropped off to 30, and then stabilized at 25.6, which still seems bogus. Traffic was good - being a Sunday morning I was able to hold a steady 70 MPH. Once I got off the freeway the mileage dropped off to 23. On the way home traffic was a bit heavier, and when I got home, the DIC was reading an avg of 20.3. Anybody else see wild readings like that? Is it possible to have brief periods of super high mileage numbers, which avg out in the long run? 25.6 MPG sure looked good on my dash while it lasted. :)
Sounds normal to me when you consider the logic behind how it works. It's calculating AVERAGE fuel economy starting from the time you reset it. If you happened to hit reset while coasting down a hill, the calculation starts at that point when you're travelling a large distance relative to fuel consumed and your mileage looks abnormally high (it's technically correct though). Similarly, it you hit reset while sitting at a light, your mpg would be zero until you started moving.

Ok, I've heard that the DIC's mileage is pretty accurate, but I had my doubts today. I reset it this morning on the way to work, and it shoot way up to 40! It didn't last long, just seconds, & quickly dropped off to 30, and then stabilized at 25.6, which still seems bogus. Traffic was good - being a Sunday morning I was able to hold a steady 70 MPH. Once I got off the freeway the mileage dropped off to 23. On the way home traffic was a bit heavier, and when I got home, the DIC was reading an avg of 20.3. Anybody else see wild readings like that? Is it possible to have brief periods of super high mileage numbers, which avg out in the long run? 25.6 MPG sure looked good on my dash while it lasted. :)

On my previous gas engine the DIC gave an instant readout, and it was pretty accurate. It gave a constant update on the mpg. When it was in avg mpg it was a steady rate with slight fluctuations. With the diesel it does not have an instant readout, but I note that it is erratic when initially reset on the avg mpg. Readings of 10 mpg going up to 14 mpg then averaging around 12 mpg. example readings only. This leads me to believe that the diesel consumption is more difficult to monitor than gas and has to be based more on time/distance to be accurate. I find the DIC to be within 1 -2 % of actual consumption, so with inaccuracies in fills, pumps etc. I think it is a good measure of performance. Traveling on level at constant speed the LMM give great mileage, steep hills, stop and go traffic really kill it's fuel consumption. Rapid acceleration is like opening a hole in the fuel tank. On level I get a consistent 21 -22 mpg traveling a constant 62 mph on rural roads. Truck is now getting 10 -15% better than my gasoline truck and diesel fuel is now 2/3 price of regular gas. a real bonus.

i would love to trade my truck in to get one of these new trucks. i love the new body style, but i would be way upside down in it if i did. i guess i will be looking when i am closer to 100k miles. got 88k on it now, but it wont take me 4-5 months to get there. as for mileage, with my lb7, i get 19-21 on the hwy if i am going 80+, and get 17-18 if i am going under 80. doesnt make sense, but that is the way the math works out. so guess what, i run 80+. just my $.02

i would love to trade my truck in to get one of these new trucks. i love the new body style, but i would be way upside down in it if i did. i guess i will be looking when i am closer to 100k miles. got 88k on it now, but it wont take me 4-5 months to get there. as for mileage, with my lb7, i get 19-21 on the hwy if i am going 80+, and get 17-18 if i am going under 80. doesnt make sense, but that is the way the math works out. so guess what, i run 80+. just my $.02

The LB7 was my first and I noticed the same thing. I took a trip to Vegas and once I made that left turn as Bakersfield I put my fut in it and cruised at 85 and 90mph, it always shocked me to get a little more that 19mpg on that leg, and on the previous legs were I was running 75 I would have around 17 mpg. I took the trip the 3 times and had the same result each time.
I never mentioned anything for fear of being laughed off the board, but I tell you it happended, oh and for whatever reason the DIC always showed 20-24 mpg, so I had to hand calculate to get the correct reading.

yeah, i dont have all that fancy stuff to tell me what kinda mileage i am getting, which i wouldnt trust it anyway. but the faster i have gone, better mileage. i did get 22mpg one time on my way home from houma, la. i was going 90-95. i dont understand it, but a calculator cant lie when you read your miles and fill up. i like my truck, i really do. but them new ones sure are looking nice

Ok fellas. I have a 2007 GMC 2500HD Dura/Allison combo. Stock tires and hight with a 26 gal tank. I have 2500 on the clock and I avarage 10-11 mpg all the time. So far the best I have seen is 320 miles on a tank after the little fuel light came on. I'm not really excited about the milage, but I love the truck and i'm hoping I will see some improvments as time goes on.

600 miles on my 3500HD and I'm getting 17mpg since my last fill up. This truck runs GREAT.

I have a 2002, 2500hd extended cab as well. I never have gotten less than 18 miles to a gallon, and usually 19, city driving. I don't have 4 wheel drive.
i know not a lot of these are out there yet in all areas,we have sold a few up here.my question is to the guys that do have them,what are you seeing for milage?just wondering if its varrying widely like past models

I got 11.7 hand calculated on my first tank with the sorry PPE programmer on level 2. But hey I only was hoping for 12 so I am almost there.

just picked up my truck 3 days ago I put 275 miles so far 12.9mpg on comp pic comming soon crewcab longbed

1300 miles DIC reads 15.5 I have to keep it just below 1500 RPM to see an increase in mileage. Got it up to 15.8, but couldnt take it anymore and had to put my foot in it.

It's funny, it only takes a few redlights to bring the average economy way down real quick, and about 30 highway miles to start bringing it back up.
Whats up with that?

But hey, I was getting 8 MPG in my 05 2500 HD 8.1 Silverado so I aint complaining...

Drove from DC to Ohio, just under 400 miles, got 18 mpg. I now have about 900 miles on the truck.

I just picked up my 2007 3500 DRW (new style) yesterday (YEA HOO!). Took my father-in-law out to eat for an early father's day dinner. We went from SW Ohio to Richmond, KY (Sonny's - awesome family barbecue place). Put over 300 miles on it. The DIC read 16.6 when I pulled in to my drive. I haven't had to fill it yet. I will do a hand calculation then.
This truck is just wonderful to drive. I will post pics as soon as I can!

i have a brand new duramax lmm 4 door 4x4 with 3,000 mile and im getting around 15mpg in town. i recently took a trip and got 19.3 doing 70 to 75 on highway. when i figiure it paper my DIC has been pretty close to the exact mpg. i did cut my muffler off though. i just got my ppe programer and modified the intake but it hasent helped mpg.

Got my Silverado 2500HD LTZ Duramax (LMM) crewcab, standard box last week and love it. With 250 miles I'm still on my first tank but the DIC - with a combination of city and mountain driving - shows I'm averaging 15.7 mpg. My only complaint so far was that I got it dirty on Sunday driving a dusty mountain trail. I can't wait to hitch my trailer to this baby and take off.

http://www.intersol.us/new_truck.htm


Bernie

I just made a trip to Texas with my family and a friend who also has a new LMM. The entire trip was about 2000 miles for me from AZ. His has around 6000 miles on it and mine has about 2000. We were both pulling horse trailers of similar weight. He got around 13 mpg, while I got ten. Based on these figures i expect things will get better the more the engine gets broken in.

You will see a gain in fuel mileage, I also run biodiesel, don't know if that helps or not:)

i just bought mine today and the computer is reading around 14mpg. i drove around 60 miles in the city and the fuel gauge has barely moved. looks like i am halfway between 7/8 and Full.

i will be driving 5 hours one way friday then making the return trip monday so i will get a good estimate on highway mpg

OK, beings we can't always drive on freeways, flat ground, no wind, the moons aligned just right, etc... We need to average everything out so that we don't fool ourselves :)

Sooo...I just made a 650 mile trip that included ~500 miles of freeway (78mph) that has many uphill and downhill grades, lots of variable winds to 30 mph, tank filled to the brim each time and the results were 15.1 mph on the hand held calculator and GPS.
This is with a 6" lift, 35" tires and the main variable would be the Edge Juice/Evolution set at 2.

Also,
Someone mentioned that weight didn't really matter.
Living in the Rockies and pulling a boat (12k lbs) the theory of "weight doesn't matter" is soooo untrue.
I can pull a 6k lb trailer like it wasn't there. Throw on the big 12k lb trailer and watch the fuel economy disolve.

Anyway, I am happy with 15mpg with 1900 miles total so far :D

Dave

OK an update from post #21 he now has 7000k miles on the truck and he is barly making 13 mpg is there anything he can do to up his MPG like a tuner or somthing he has a light foot and drives around town mostly, thank's. Dave

Mines usally say 15.2 mpg thats mostly city.

I have been reading the PPE tuner and egr block off plate is a good combo. Put it on a mild setting and it should help. Possible 2-3 maybe 4 mpg more.

I've had mine 3 weeks today - a little over 1700 miles. Commute from 8300 ft. to 5300 ft. over 35 miles. Also have done two trips of about 90 miles each way pulling a trailer w/2 ATVs. Overall mileage from my first fill to latest fill is 16.7. Highest mileage on a single tank was 17.4. Highest reading I've seen on the DIC was 18.9, but that wasn't over a long distance. Tank to tank the DIC and the hand calculation are usually within a tenth or two of each other.

I have just over 3000 miles on mine. It has had an overall average of just under 13 miles a gallon. When I reset it after a fill up, it has times where the average is quite a bit higher (18 mpg) for a short while, then it drops (probably due to the regen cycle. It would be nice if there was some sort of indicator when the cycle is on. I wonder sometimes if it can run more than once on a take of fuel.

There is always going to be fast reading changes soon after resetting the DIC. The guage shows an average MGP number - Where I usually fill up I have a six mile run on the interstate before exiting to go home. The DIC will show anywhere from 17.5 to 18.5 while cruising on the interstate. My next five miles are more stop and go so you can watch the level go down. By the time I get home it's at 16 or so.

Had I filled up the tank, reset the DIC and then driven 200 miles on the interstate, the DIC would stay at 18. Then, if I did five miles of stop and go, it would barely move since the five miles of poor MPG's are only a small part ot the total miles traveled since the reset.

I'm averaging about 15 for all types of driving - highway, city, towing and not towing. The same type of driving at the same speeds got me 9.5 MPG with my 2500 8.1L gas. Overall I'm pretty happy and it's not even broken in yet.

I seem to be getting a pretty consistent 12 mpg with a 6" Lift and 35's......

Can't say I am all that disappointed....all things considered.

DIC and hand calc within .1

I had all the fluids on the truck changed the other day, engine oil, trans, diff ect. As of now, the truck is running in the 12-14mpg on the road and 14-17mpg on the freeway. I sure hope it keeps this up and I'll just be peachy all the time!
Fuzz

I seem to be getting a pretty consistent 12 mpg with a 6" Lift and 35's......

Can't say I am all that disappointed....all things considered.

DIC and hand calc within .1

If you haven't had your speedometer re-cal'd then you need to compensate in your calculations all the way around. There is a 15% difference from stock tires to 35's.
12 X 1.15 = 13.8mpg.
Add 15% to your trip mileage and then divide by gallons used at the pump.
I have verified this with GPS as I have the same 6" and 35's.
I consistently get right at 15 mpg on the road and 10 towing 11k lbs.
I do have an Edge Juice/Attitude which helps a bit I believe.

I have only one thing to add boys. Have faith when 20K miles approaches. These mileage threads remind me of the LBZ mileage threads. Notice how that constant drone has died out? We are all getting better mileage now!

i've got around 1000 miles on the truck now. daily driving to/from work, mixed highway and stop and go traffic with city streets, up and down hills, around 42 miles roundtrip a day. hand calc at the pump, i get around between 15-16mpg. i've seen DIC between 14.2 to 17.8 every tank. i reset DIC every fillup.
my previous truck was a No Fear Nissan Titan, 6" lift with 35" meats. hand calc mileage was always between 12-13 if i always babied her. if i ever got on it, then i was seeing 10-11mpg. nice truck though but luv the D-max

Hey folks, Got my 2007 Crew cab short bed about 6 weeks ago. have 1700 miles took 1 trip out of town about 700 miles in right after I got it speed limits were mostly around 55, so I got around 20 on the DIC and hand calc real close. but around town that number really drops to 14 - 15. My older 2004 duramax got 18 around town and 21 - 22 on that same trip. would have expected much better out of the new truck with the new 6 speed transmission running around 1500 at 55 but just ain't so.....

I have about 6500 miles on my LMM CC 4X4 and hand calculated 18.2 for a 900+ mile trip last weekend. All but 100 miles were at highway speeds of 65 to 80. It is getting better and the DIC is very close.
PJ

My truck has 1500 miles on it now and my mileage has gone up with each fill up. My first fill up averaged 16.4mpg and has gone up around .5mpg each time. The last fill up ended up averaging 17.8 on the trip computer. I got 388 miles out of 21.5 gallons which actually works out to be 18mpg. I'd say I average about 70% town and 30% highway at about 80mph. So far I'm pretty impressed with the mpg and the truck overall.

I went up to houston today about a 250 mi, round trip. I was gettin anywhere from 18 - 18.5 runnin between 65 and 70.

Im gonna be making a trip from Kerrville to Dallas,then to Austin... Austin to Houston, then back to Austin, then finally to kerrville. Ill let you know what my fuel economy will show. I wont be hauling anything except a$$ to finish this ridiculous family outing.

i went on a trip from Houston to corpus and back to Houston and i saw mpg hand calculated.

i went on a trip from Houston to corpus and back to Houston and i saw mpg hand calculated.

How much was your mileage for the trip?

Jim

im average 15.5-16mpg thats 3/4 town and 1/4 on highway

Just traded my 98 Dodge 3500 Quad Cab Cummins 4x4 Dually for an 07.5 3500HD LMM Duramax Crew Cab 4x4 Silverado LTZ Silver Birch / Ebony Int. Just got home from dealer have 210 miles on it and DIC showing 14.9 MPG this truck had 126 miles on it at the dealer cause they had to do a swap to get me what I wanted, the rest are my miles: freeway at first, then 40 mi. of 2 lane highway with lots of hills and curves. Love it so far, WOW!!:driver:

Did notice the Regen issue that everyone talks about yesterday. I was driving down the interstate where I normally get 17.5 MPG showing on the DIC, then all of a sudden it started falling tick by tick. It went down to 11.8 and stayed there for about 30 miles, then started ticking back up. It still did not get to the 17.5 MPG on the DIC, before I got out of the truck, but it ended up at 12.6 MPG. This is the first time I have noticed that happen.

14.7 With about a 50/50 split of city and highway driving according to the DIC.

I have 650 miles on LMM and I am seeing 17.5 mpg. At 29 miles, I was getting 13.5 and it progressed steadily to the 17.5. I suspect that it will continue to improve.

I have a 2007.5 HD 2500 4 door LMM with 2250 miles and I am getting 15.1 mpg. I have noticed that as the drive it more and put more miles on the truck mpg seems to be getting better. I use Lucas additive every fill up. I am not sure if that is helping or not.

Drove my new truck the 50 mile trip to Monterey from my house today, took care of some business, then topped off my tank and reset DIC, drove home, first 8 miles of freeway, then about 2 miles of 40 mph road with traffic signals, then 40 miles of 2 lane highway as I described in my last post, when I pulled in my driveway DIC was showing 16.3 mpg truck now has 320 miles on it. Since this was the first time I filled the tank since I bought it, I haven't done a hand calc yet, wouldn't be accurate till next fill up. I'm happy with that mpg so far considering truck is not broken in and it should improve as time goes on. Not bad mpg for a dually 4x4:chevy:

07.5 3500HD LMM CC Dually 4x4 :D
01 VW Golf GLS TDI 42 mpg:cool_shad :driver:
I LOVE MY DIESELS:D :D

Just picked my new truck up at the dealer and drove 200 hundred miles home. Said I got 19.5 doing mainly 60mph on highway. Not bad for a new motor.:)

4k miles, 22mpg freeway, 18mpg town :Moon:

Almost 10K since May... Towed 24' TT 6000 miles FL to Grand Canyon & back ~5000 lbs... almost 12mpg average... ~70mph on interstates...

Get 20-21 doing 70-75mph on flat interstate...

16+ around town...

Awesome truck... need bigger tank!

around 60 will give you maximum mpg , every mile an hour over you give up mpg's.:)

First tank 95% city driving, 13.3mpg.

Drove my new truck the 50 mile trip to Monterey from my house today, took care of some business, then topped off my tank and reset DIC, drove home, first 8 miles of freeway, then about 2 miles of 40 mph road with traffic signals, then 40 miles of 2 lane highway as I described in my last post, when I pulled in my driveway DIC was showing 16.3 mpg truck now has 320 miles on it. Since this was the first time I filled the tank since I bought it, I haven't done a hand calc yet, wouldn't be accurate till next fill up. I'm happy with that mpg so far considering truck is not broken in and it should improve as time goes on. Not bad mpg for a dually 4x4:chevy:

07.5 3500HD LMM CC Dually 4x4 :D
01 VW Golf GLS TDI 42 mpg:cool_shad :driver:
I LOVE MY DIESELS:D :D

I know that route well and that is some good mpg! Even better since it's a dually. I have never checked my mpg on that route because I figured it would be around 10 mpg because of how windy and slow and hilly it is.

On a 100 mile highway trip i got 18.5 mpg going about 80mph. On the way back i put on 33/12.5//20 Toyo Mud Terrains and got 12mpg but i did not reset the tire size. So call it 13mpg with bigger wheels and tires.

Wow, the larger tires make that much difference???? That's almost 5 mpg!!!!! :mad:

It's interesting to see the debate on mileage. It's drastically different depending on driving habits. Brand new , I got just over 20mpg doing approx 60-65 going easy on it, driving 1500 miles to florida unloaded I got 18.7 pretty much the whole way, Irritated by sudden drop of mpg everytime it regens. (Can't wait to straight pipe it, once someone works the bugs out of the programming issues.) Coming home towing over 10k I got about 9.2mpg, high speeds with stop and go.Now driving around town with a heavy foot, I'm averaging only 14.7 hand calculated. But I really don't care. It's still better than the wifes 4.2 I6 envoy, go figure.

just over 3,000 miles getting in the nieghborhood of 15.3 mpg not bad because i cant keep my foot off the floor i did go easy for just one tank and was around 19.3 or so

Hey fellas, I am brand new here.
I have 5000 miles on mine, 6" lift, 35" tires, I am getting 16.5 calculated and on the DIC. I tried a Super chip flash paq that didnt help any I am waiting on the New Triple Dog to come out, should be here soon so they tell me

I have a question about the LMM, this is my first duram x by the way.

My oil pressure only runs around 30 psi at operating temp and highway speeds, dealer says this normal. Is this normal for this engine, all of the folks I know with Dmax have the LBY and LBZ and they say theirs is around 60 psi

Mine runs around 30 at operating temp on the highway...

Hello, I'm new to the forum and just picked up my Silver Birch SLT 4x4 2 weeks ago. I'm currently getting 17.5mpg, which is from 30% city and 70% highway driving and I have around 700 miles on the odometer......

Hey fellas, I am brand new here.
I have 5000 miles on mine, 6" lift, 35" tires, I am getting 16.5 calculated and on the DIC. I tried a Super chip flash paq that didnt help any I am waiting on the New Triple Dog to come out, should be here soon so they tell me

I have a question about the LMM, this is my first duram x by the way.

My oil pressure only runs around 30 psi at operating temp and highway speeds, dealer says this normal. Is this normal for this engine, all of the folks I know with Dmax have the LBY and LBZ and they say theirs is around 60 psi

That's what my shows too. Guess it is normal.

That's what everyone seems to be saying, I guess I may need to apologize to that dealer that I called an idiot, I probably won't but may need to.

2008 ltz ccsb, 800 miles, 30psi oil pressure is what mine is running also. Fuel milege, 250 mile round trip from Hershey to NJ, 70% hiway, 30% local, 20.5 mpg, local, back and forth to work, rural roads, not hiway, not city, 15 mpg.

With almost 400 miles on my new 2008 LMM, im seeing 13-16 Average MPG's with 100% street driving...

If I hit the DIC Fuel "Check" button and clear the average fuel mialage, while crusing at about 45 MPH, the MPG reads about 21-22 MPG.

Mialage and power Gets better and better each day.

Currently running the Stanadyne Performance Diesel Fuel additive and Chevron Diesel Fuel at $3.15 a gallon in Orange Coutny, Ca.

Very Happy with the New ride!!!:D

Got around 1600+ miles on the truck now. Took a 173 mile roundtrip to see some friends. Averaged around 18.8, according to DIC, when I got home. On the way home, I drove against a head wind, which sucked the life juice from the fuel tank a little bit faster.
I pump Chevron ulsd diesel.

Interesting reports on fuel MPG, but what are the differences encountered when using ULSD or LSD or B10, B5 etc in our LMM......with or without additives???

I'm getting on average about 15.8 MPG on the DIC. I have had it up to 16.3 doing a mix of city and country road driving, but really had to be careful with the pedal to get that. Haven't had it on the highway yet for anything other than 15-20 miles at a time. It went down to 15.2 pulling my trailer for the first time, that was about 80 miles for the trip. I'm pretty happy driving a truck this heavy and getting that kind of mileage. At least I can stop my trailer with this truck without a lot of help from my Prodigy brake controller. No need for boost level 1 anymore. My 03 1500 was terrible with the brakes and I don't need the weight distribution hitch either. Mileage does go down quite a bit during regen mode and takes a while to start climbing back up. I tried Stanadyne this last tank, so I will see if that does anything, so far I haven't seen any changes. Truck has about 900 miles now. Oil pressure while cruising is 28-30 psi. Normal for this motor, I got that through a friend at GM who talked to the engineers.

Picked up the 3/4 ton 4x4 brand new at the dealership and drove it 1,000 miles to Farmington NM from D/FW. Averaged 16.2 calculated on the round trip.

Just got back yesterday from El Paso, averaged 16.0 on the way there, and 14.5 on the way back (pulling an empty car hauler)

Drove my son's '02 Cummins pulling his buddy's Jeep to El Paso and got 15.5 on the trip there. That motor has right at 97,000 miles on it. Gets 20-21 empty.

I'm hoping that one day my new Chevy will get close to that.

Interesting reports on fuel MPG, but what are the differences encountered when using ULSD or LSD or B10, B5 etc in our LMM......with or without additives???


And what is recommended the most?

My mileage has stayed very consistant 16.8mpg with me running it hard. I took it on a 150 mile road trip at 70mph got 21mpg. This tuck has insane power and we are still gaining with efi live every week.

12.49 mpg on this last tank of fuel 16 city and 24 hwy miles daily to and from work have yet to pull the trailer maby this weekend

First tank 14.8 second tank 16.6 and third tank 17.7 The first two was mostly around town driving and the last was more highway than city. Hopefully it will keep going up.

I'm averaging 15.4 in town. Got 12.9 towing 360 miles over the weekend and best of 19.5 empty on highway. Not bad so far for a motor not even broke in it. :)

By the way mine was hand cal after each fill up, I've seen 21.3 driving 60 and 20.5 doing 70

OK the worst I've got was 14.4 the best was 16.84 ( last tank) but for the most part it's 15.5mpg. I drive 85-90% hiway.

I agree Roadshark. That truck does look great and that MPG is really good for a new diesel...
So far, it seems like LMM Fuel mialage is very very similar to LBZ mialge based on what you guys are saying about your LMM trucks.

Once broken in, the LMM should get 20+ on good days crusing down the highway from what some LBZ guys have said...What do you guys think?


I have a 07 Classic LBZ with 3,000 miles on it now and we did a 700 mile trip. Averaged 20.7 MPG keeping it anywhere between 55 and 70 mph. When I first got the truck I was getting about 15 to 16 mpg. I have found that keeping the cruise control on and keeping your foot out of it really helps....

So far averaging between 17-17.5 mpg according to the DIC with ~700 miles on the truck. ~500 miles of that was highway mileage from Maryland to New Jersey and back....can't complain about that on a brand new truck of this size.

mileage results are always going to vary to some degree...a crosswind will cut your mileage as well as terrian and whether or not u are running the a/c. my 4x4 will do about 16.5 if i drive 65mph. i have 5000 miles on it and my trips are typically under 40 miles without stopping. sure wish i was getting 20 like some reports i am seeing on here!!

Update at 3200 miles. Overall mileage (hand calculated) since I got the truck - ~16.2 mpg. BUT, this includes two trips of about 200 miles each pulling my ATV trailer w/2 ATVs on board and 1 trip of about 250 miles pulling my 28' Camper. Best mileage on a single tank - 17.9. Worst mileage between fills - 11.2 (pulling the camper and only about 125 miles).

All my driving is in Colorado either in the mountains or commuting from the mountains to work in the city (~3000' difference).

I guess after over 180 posts all of which say differing things I suspect it is safe to say:

YOUR MILEAGE MAY VARY.:D

That should be the end of the thread...lol :muahaha:

thanks
Dan

14 .93 on that last tank of fuel
the truck is in the shop now and they have to remove the dash to fix a broken vent far poassanger side that is broken
and they are going to install the DIC while they have the dash apart my first upgrade :D

1GCHK336X7F514671

I am only getting 13-14 with a 3500 DRW, must be the duals. The '06 LLY 2500 was 16-17 on the same roads driving the same. Best I ever saw was about 18.5 in the '06.

Getting 14.8 mpg with ~680 miles

Starting at 150 miles on the truck, drove north on the CA coast about 185 miles. 4 stops and about 15 minutes in 10 - 20 MPH traffic. DIC average at fillup was 20.4 MPG.

I am only getting 13-14 with a 3500 DRW, must be the duals. The '06 LLY 2500 was 16-17 on the same roads driving the same. Best I ever saw was about 18.5 in the '06.

Not sure if this will help you, but I checked my tire pressure and it was 60psi front and 55psi rear on the duals from the dealer. I was seeing about the same mileage as you on rural 2 lane highway with lots of hills and curves and tourists doing crazy things in front of me, till I put all 6 at 70psi, now it seems to be 15 - 16 mpg unless it regens. best I've seen so far was 19.3mpg on the freeway with cruise set at 65mph (before I bumped up the tire pressure) haven't been on an extended freeway trip since so I'm not sure how the higher psi will affect that yet..... best of luck to you!!!

Hi...newbie here. JUST picked up my ride Friday, averaging around 13.7, but have less than 100m miles on it. Noticed that the DIC AVG has been steadily climbing since I picked it up. Just round town stuff so far..........stay tuned, I'll drop another update in a week or so.

Luvin' this ride, tho!!

I just picked mine yesterday. I test drove it wih 1.2 miles on it. Hooked up my boat to it with 7 mile on it. Drove it 300 miles last night and got only 8.9 MPG. I hope this thing gets ALOT better. I will definetly need a larger fuel tank. I am used to my 3500 dually and the massive tank. I filled up 3 times already.

Is your right foot glued to the floor?:)
Mine gets 20-24 on the highway empty and 11-12 towing my 40 foot gooseneck with 4 cars in it.

hi I just got my new 2007 Lmm, auto trans, new body style truck satureday.I went on the road for the break in drive sunday, with the dic reset and the tank full,I ran a mix of highway and small town stop and go, I kept her at 55 on the highway for break in. I am running a crew cab short bed, 4x4, tires are lt245/75r16e at the end of 330 miles my dic said I was getting 19.6 miles per gal, at one point while driving at highway speeds the dic said 20.7 miles per gal. When I used a light foot my truck will shift gears at, 1700 rpm's , when I run a heavy foot she shifts at about 2100 rpm's I think this is why some of the mile's per gal reports are coming in all over the place. I love this truck I now have 550 miles on her and I am leaving from fl to go to maine for two weeks with are 30 foot, 8500 lbs trave trailer. I will post when I get back. does any one know how many gal the tank is on the short bed? the book said 34 I dont think so?

Short bed: 26, long bed:34.

thank you

DOSWACKO -- I call Bullsh*t. I have a 2008 LMM just got home from towing my toyhauler to St. Anthony ID and it got 6.1 mpg. Empty it hasn't seen even seen 14. Downhill water temp stays at 210 and uphill she likes to run at 220 to 250. That's when the temp outside is 80 to 85 degrees. Needless to say I am not getting rid of my 2005 yet. And no it is not stock. I have tried it both ways.

Sounds like theres something wrong with your truck or you have a very agressive right foot. The worst hand calculated mpg I've gotten out of a tank was 16.4, and that was alot of town driveing and the first 350 miles of the trucks life. All my fill-ups have been at 380+ miles and most I've put in it was 23 gallons. If I reset the DIC on the highway it usually ends up at about 21-23mpg depending on speed and the highway. I call unbullsh*t

I agree with dmaxdon....I have 50000 plus miles on my LMM, so I think I know my truck pretty well. I get 20-23 MPG consistantly on the HWY unloaded. It generally settles around 21MPG. Sure if I have lots of headwind or hilly terrain it's lower. But I also travel in the 65-70 mph range, and I don't have a heavy foot, most of the time:rolleyes:
I'm on the HWY 98% of the time, either unloaded or loaded.
Pulling trailers my mileage is between 10-13 MPG. I've had some as low as 7.5MPG and the last 5th wheel I pulled was around 9.6MPG but I was pushing it a bit because I had to make the dealer before he closed.:)

All this according to the DIC or hand calculated......It seems the LMM's are getting decent mileage....sure if I push 75mph, I'm getting about 18.5MPG. Also when it goes into regen. it drops to about 12.5MPG. for about 20 minutes:eek:
By the way the DIC appears to be extemely accurate.

No Bullshirt;)

17mpg @81-85mph this evening from Spokane to Seattle. 1100 mi on the truck. Mostly empty.

First tank of fuel with the 2008 dually 13.2.. empty

2007.5 1ton dually 4x4 LMM duramax haven't seen any posts here on towing mileeage thats all i have been doing 4 weeks since purchase 10,000kms on truck all towing have a edge programmer i get around 10.3 - 10.7 miles per gallon but now mind you my trailer empty is 7000 lbs and loaded am averaging a total weight of 15,000 or so lbs not bad i guess thats average speed of 105 kms get around 450 kms to the tank of fuel sorry for the references beng in KM's lol but us canadainas we like to be different lol

750 miles on '08 3500HD SRW...city & hwy driving. Avg. MPG is 17. I'm not unhappy with that.

07.5 2500 4WD. 17.8 mpg running empty, mostly on 50MPH roads. I'm getting a steady 10.2 hauling my 8,500 lb 5'th wheel. Driving style is moderate... I enjoy hearing that turbo whine... I have 4,500 miles on the truck.

583 miles on 2007 2500HD 4x4 extended cab, city and highway average 19.3 mpg non-towing. I'm happy, it should go up as the engine breaks in. Curious as to what I'll get when hauling the 40ft fifth wheel toybox.

I just got back from Ocean Isle, NC, about 400 miles each way, got 14.3 on the way over running 77 to 80 most of the time on the interstate, 15.56 while we were running around there and 14.7 coming back pulling the jet ski at 80 to 85. Kind of odd that I got better mileage coming back pulling something and going from sea level to over 3300 ft asl than I did on the way over without pulling anything. I did run the cruise most of the way over and only a little on the way back. It's a 07.5 dually crew cab and only had 1003 miles when I left and we put a little over 1000 on it the whole trip. I'm really curious to see what it gets with our 9000 lb. fifth wheel too.
I'm hoping it gets better when it gets a few more miles on it but it's still better than 11.5 to 12.5 I got with my old 6.0.

OK the worst I've got was 14.4 the best was 16.84 ( last tank) but for the most part it's 15.5mpg. I drive 85-90% hiway.

17.3 now:D :D :D
that's great!!!!!!

My 07 3500 4x4 Dually was showing a little less than 10 when I took delivery with 62 miles on it.

Creeping up on 1,700 miles and reset the meter yesterday. Drove it in town for 60 miles and it showed 11.9. Hooked up the boat to it this morning and drove it in to the shop. It went downto 11.5 immediately and was back up to 11.8 when I got here

Have not checked or reset the speedo with 265/75/16 tires

i have a 07.5 3500 dually and average 15.7 mpg highway. i have 2200 miles and am hoping mpg continues to increase. when i first took delivery of truck it had 6 miles and was running 14 mpg highway

Just took my o7.5 for a 450 mile ride, Mostly interstate, and thenm local roads for about 75 miles, hand cal'd mgp was 18.4, No load, 4 passengers. Total miles on truck, 650

Just checked my mileage today with 683 miles on the odometer. I did a mix of 85/15 highway/in town driving and hand calculated 17.1....I also reset the DIC MPG average at the initial fillup and it stated I was getting 17.5 when I filled back up the 2nd time.

Not bad at all considering the engine is brand new.

Corsa Cat Back, AFE Pro Dry, EFI Live. 18+ Hand Calculated Average, 21+ on freeway. ;)

A bit over 1200 miles on my rig now. DIC showed 20.2 on easy, back-road driving. Then hooked up my 10k lb trailer and towed it to the top of a local (5500') mountain. Averaged 9.6 up and down...but it's a very hard pull up.

My new D/A is showing 14.9 with 600 miles on the rig.

2008 chevy c/c s/b z71- I now have about 600 miles on it and am getting 15.6 hand calculated.:rolleyes:

the only valid numbers for mpg are highway. I could drive to work one day at 4a.m. and come home at 2p.m. and hit light to no trafic and get 16mpg with a comute time of 20min and could drive the same route the next day at 7a.m. and 5p.m. and get 10mpg and take 50min. there are way to many variables involved in any stop and go driving to compare mpg. but highway you go a steady speed for a long period of time getting a more comparable number. I am getting 18mpg at 65mph and 15.2mpg at 75mph empty

Update: Have about 250m on ODO about half of that highway, the rest 'round town: DIC is showing 16.3 and climbing steadily. Will update again.

VERY happy with truck.........

With 15k on the clock I am hand calculating 19.14 on the highway, and 14.74mpg in town. I am happy with the mileage on the highway as it is comparable to my 06 Cummins, although I would like to see a couple more mpg in town especially with the small 26 gallon tank.

my 07.5 ext cab long bed with 650 miles on by hand calc is getting 18.5 mpg. I see from the responses that there are like two groups, thoughs who are getting in the 10 -14 mpg range, and thoughs who are in the 18 - 20 range. One point nobody has mentioned is what is the axle ratio. My truck has the 3:73 gears, what do you guys that are in the 10 -14 range have??

For thsoe that done have your mods listed in your sig or garage could you post them. Im particularly interested in the ones getting in the high teens on the highway what mods you have and current miles on the odometer.

i have a lmm 4k miles 2wd cc sb and i get 13mpg in city and 15mpg hwy it suck and i dono why i dont drive that bad! but still better them my old 6.0


can any one tell me why my mpg sucks

How fast do you drive on the highway

Another update....I filled up this morning and on my way back home I refilled and my mileage (hand calculated) was 17.11 MPG (my mileage in between fillups was approximately 185 miles). That was approximately 90% highway miles with 1500 miles on the odometer.

To adrexco: the only ratio offered with the duramax is the 3.73. I don't know what could be giving those guys such bad mileage besides their right foot.:confuzeld The worst I've ever seen out of my truck is 16.4 average with almost all town driving. The only time I see bad mileage is that painfull 20 minutes when I get 11mpg on the highway, and that will be gone very soon. (thank you EFI:hail: )

hwy cruz at 80