Ive had my new LMM for 3 months now with just about 2800 miles on it. The mileage is not the best! I do have a six inch with 35's so im not expecting the best mpg but come on 10 mpg????? I dont have any major mods done yet other than a AFE stage 2 and ive got the banks six gun! The six sun helps a little maybe get 11.5 mpg with the six gun!Any sugestions on better mpg?

What were you getting before the lift? Is your milage hand calculated? Have you re-calibrated the speedo? 10 mpg doesnt sound right, even thought you have lift you should be able to get 15 mpg or better. Why some people get terrible mileage and some people get fantastic mileage I'll never understand, I just hope Im a lucky one when I get mine.

Hand calculate it. DOn't go by the dash computer. I get 15mpg.

What were you getting before the lift? Is your milage hand calculated? Have you re-calibrated the speedo? 10 mpg doesnt sound right, even thought you have lift you should be able to get 15 mpg or better. Why some people get terrible mileage and some people get fantastic mileage I'll never understand, I just hope Im a lucky one when I get mine.Thats hand calculated with just around town driving! The speedo has been re calibrated! I do not have a heavy foot either! I was told the new Lmm's dont start getting decent mpg's till after 6000 miles but who knows?I was getting around 13.5 around town before and about 17 on the highway before the lift and tires!

Ive had my new LMM for 3 months now with just about 2800 miles on it. The mileage is not the best! I do have a six inch with 35's so im not expecting the best mpg but come on 10 mpg????? I dont have any major mods done yet other than a AFE stage 2 and ive got the banks six gun! The six sun helps a little maybe get 11.5 mpg with the six gun!Any sugestions on better mpg?


U might have hit a regen and it not went thru the entire cycle being that u did a lot of stop and go driving. Get her on the interstate and see how she does around 65-70mph. Also, are u driving it hard? Keep in mind that these trucks give a few mpg better if u keep the shifts under @2000rpm or under. If u do fast take offs and wind up the rpms it will hurt your gas mileage.

I was getting 16-18 stock with 200 miles... a lil better now with 15k.... I thought the six gun wouldn't change the tire size yet? Check to make sure the size is correct. Did you hand measure your tires? If you have a GPS you can check to see if your speedo is correct or close... 10mpg seems very odd.

I was getting 16-18 stock with 200 miles... a lil better now with 15k.... I thought the six gun wouldn't change the tire size yet? Check to make sure the size is correct. Did you hand measure your tires? If you have a GPS you can check to see if your speedo is correct or close... 10mpg seems very odd. I changed it with the pro comp programmer made by hypertech to calibrate tire size so i know thats right! gps checked it also and it was dead nuts on!

U might have hit a regen and it not went thru the entire cycle being that u did a lot of stop and go driving. Get her on the interstate and see how she does around 65-70mph. Also, are u driving it hard? Keep in mind that these trucks give a few mpg better if u keep the shifts under @2000rpm or under. If u do fast take offs and wind up the rpms it will hurt your gas mileage. I will try that! I dont drive it hard at all ! I like to call it the "Dairy Queen" crusier!:D

I was getting around 13.5 around town before and about 17 on the highway before the lift and tires!

Well, there you go.

Either the big tires are costing you the MPG's or the speedo is not really calibrated for the new tire size. I would bet that the calibration is off. As said above, check your speedo with a GPS or get someone to pace you to see how accurate it is.

Well, there you go.

Either the big tires are costing you the MPG's or the speedo is not really calibrated for the new tire size. I would bet that the calibration is off. As said above, check your speedo with a GPS or get someone to pace you to see how accurate it is. Its been re-calibrated and checked with a hand held gps and is right on ! It must be the tires and lift!

Thats hand calculated with just around town driving! The speedo has been re calibrated! I do not have a heavy foot either! I was told the new Lmm's dont start getting decent mpg's till after 6000 miles but who knows?I was getting around 13.5 around town before and about 17 on the highway before the lift and tires!

You will crush your fuel economy with just in-town and those 35's. You really can't evaluate fuel economy with stop & go drivein, other than to say "for this tankful, I got...". there are just too many variables.

To really determine the effective mpg's of your rig, you have to do steady state hiway driving, preferably on a day with little or no wind.

10 seems low to me. I am gettiing the worst mpg's I have ever got right now. 13.8 hand cal. 13,000 miles on the truck. I know why I am getting such low mpg's (300 hp tune from ppe :D) but you I would say regen, tires, lift maybe.

What kind of MPG are ya talking... U.S. or CAD. I still use 4.5L for a ga I think U.S. was 3.8L....mine is about 19 CAD hand calculated ....about 22 mpg if no baggin it...just checking...

I get around 13-14 on an average tank but when I beat on it just a little my mileage is around 10. I don't even bother figuring it out anymore, can't do much about it except buy a small car and that's not going to happen. Some of the mileage stories I hear on here, are just fairy tales to me. JMO

I get around 13-14 on an average tank but when I beat on it just a little my mileage is around 10. I don't even bother figuring it out anymore, can't do much about it except buy a small car and that's not going to happen. Some of the mileage stories I hear on here, are just fairy tales to me. JMO I hear ya. Im right there with ya!!:cool:

How many miles or KM's do u guys have?

How many miles or KM's do u guys have?
I only have 2800 miles on mine!

I have 35000kms its getting better. But with DPF DELETE got real good...

When I do a lot of around town driving it can get down to an average of 10. If I dont hit a decent highway for a week, it will get low. The thing sucks fuel when you just rip around town, in and out of the driveway, to the store, doing errands, idling etc. Keeping it under 2000 rpms helps but I for some reason try that but I still can't focus on keeping it below that.

I got stock setup too. When I do a road trip, it gets to the 18-20 range.

Anyway I wouldnt be that suprised. With the winter diesel this winter, I was averaging between 10-13 around town all week long.

im at 13.8-14 average with both around town and freeway. but the around town driving kills the MPG's. and dont get me started on the regen around town..... 5 MPG's during it. i drove from the gas station to home with it in regen and it was 10miles home all streets and i used .5 gal fuel......

i drove from the gas station to home with it in regen and it was 10miles home all streets and i used .5 gal fuel......

That's 20 mpg. Pretty good.........

Yup mileage with a lift and tires kills MPG. Im getting about 13 or so p/gal. 10mpg does sound unusually low. Freeway I get about 14mpg keeping her under 70mph.

Where are you? The reason I ask is that we still have winter blend fuel (for another week) where I live and depending on the formulation that's a 1-5mpg hit. I can see my fuel mileage improve as the blend keeps changing. Worst mileage I had this winter was 7mpg with just short trips and temps below 0F. This last weekend it was 18.5mpg of mostly freeway driving droping to 14mpg in town. 13000miles on the truck

Seems low to me but never had a lift either. Seems many end up changing differtial gears to get back in the correct zone. Maybe 4.10s or 4.56s

Brian

i'm getting about 13 and 14 MPG and I have 22" wheels and 35" tires but I have a DPF delete and a tune from NIck @ duramaxtuner.com check out the pics in the garage.:cool:

Are you getting an BioDiesel with your fuel? I went down to 10-11 with BioDiesel. Now back up to 14 - 14.5 in town with 100% D2... Just a thought. You may also have the constant regen issue that is killng your mileage. There is a TSB about it out, although good luck I can't the dealer to do the ECM program upgrade or change the air filter...

Letting the "big boys" in Detriot figure it out now. Either fix it or replace the whole truck...

A guy around here bought an early LMM (first NBS Duramax I saw)and all he could get out of it was 10mpg stock. He sold the truck after two months, the new owner said it is not any better now after about 8 months or so, not sure the miles on the truck.

with lift and 35's im about 14 if im nice to it dpf intact for now

My worst tank around town was 8.75 MPG. Usually all in town driving nets me an average of around 10 MPG or below, no lift stock tires and not a heavy foot.

I drove my dads 2006 LBZ today and i saw on the display 19.7 mpg! I asked how the he** he got 19.7mpg out of it and he laughed and said he was getting 22.5 last week on a 10 hour trip to New Mexico!!I couldnt belive it. Im starting to think its got a lot to do with the DPF as being a big factor in my mpg!!!!:mad:

I drove my dads 2006 LBZ today and i saw on the display 19.7 mpg! I asked how the he** he got 19.7mpg out of it and he laughed and said he was getting 22.5 last week on a 10 hour trip to New Mexico!!I couldnt belive it. Im starting to think its got a lot to do with the DPF as being a big factor in my mpg!!!!:mad:
Welcome to the conversation. We have all found it takes about 2-3 mpg easy to drive the DPF. Along with about 30hp and 40ftlbs.

Ive had my new LMM for 3 months now with just about 2800 miles on it. The mileage is not the best! I do have a six inch with 35's so im not expecting the best mpg but come on 10 mpg????? I dont have any major mods done yet other than a AFE stage 2 and ive got the banks six gun! The six sun helps a little maybe get 11.5 mpg with the six gun!Any sugestions on better mpg?
is your parking brake on? :lol: as many have said its probly the dpf clogging up and starting to burn off then you shut it off. so it starts again the nesxt time you drive it and dont drive at sustained speed for it to burn 100% off. take it off!:rolleyes:

Welcome to the conversation. We have all found it takes about 2-3 mpg easy to drive the DPF. Along with about 30hp and 40ftlbs. DPF is coming off this weekend!!!!!

DPF is coming off this weekend!!!!!
You're gonna have to ditch the 6-gun. They don't support non-DPF.

You will need either a PPE or Quadzilla programmer / unless you want to go laptop style and do EFILive.

rstarr,
get a ppe so it will support the dft delete as pa32 stated. also start savin up for a SC!

You're gonna have to ditch the 6-gun. They don't support non-DPF.

You will need either a PPE or Quadzilla programmer / unless you want to go laptop style and do EFILive. Got a buddy who's a tuner who is going to use efilive !

let us know how much your mpg goes up with out the dpf

a ton I bet!

It should go up slightly. I would hope that your mileage overall would not be that low, something has to be wrong...

when my truck was stock i was getting around 15.5 to 16.0 thats a combination of stop and go city driving and 55-70 mph open roads.. that was decent to me.. i installed my lift at 2000 miles and now it has 8000. with the same style driving i get about 12-13.8that is hand calculated mileage and my speedo is off about 3 mph. That 12-13.8 calculation is taking into concideration that i add the 3 mph back to my mileage. anyway my tires and lift also hurt my fuel mileage but soon to fix that...

Are you getting an BioDiesel with your fuel? I went down to 10-11 with BioDiesel. Now back up to 14 - 14.5 in town with 100% D2... Just a thought. You may also have the constant regen issue that is killng your mileage. There is a TSB about it out, although good luck I can't the dealer to do the ECM program upgrade or change the air filter...

Letting the "big boys" in Detriot figure it out now. Either fix it or replace the whole truck...
Interesting........We have burned B100 for 3 years in most every brand of motor,other than the Navistars, and consistently only lost 6-7% in mileage. Large trucks, pickups, every machine in the business. Oil analysis showed excellent results each change, due to the better lubricity than with ULSD, and visibly less smoke..........40% reduction?, bad fuel.

Ive had my new LMM for 3 months now with just about 2800 miles on it. The mileage is not the best! I do have a six inch with 35's so im not expecting the best mpg but come on 10 mpg????? I dont have any major mods done yet other than a AFE stage 2 and ive got the banks six gun! The six sun helps a little maybe get 11.5 mpg with the six gun!Any sugestions on better mpg?


I think you have over looked one thing. Width of your new tires will play a big part in cutting mpg. I first noticed on my vette after adding 1.5" in width to each rear tire. MPG went from 26-28 hwy to 19-20 hwy, and that was the only mod made. Also when I took my stock tires off my truck and replaced with 35" I went from 17mpg to 12-13mpg hwy.

Interesting........We have burned B100 for 3 years in most every brand of motor,other than the Navistars, and consistently only lost 6-7% in mileage. Large trucks, pickups, every machine in the business. Oil analysis showed excellent results each change, due to the better lubricity than with ULSD, and visibly less smoke..........40% reduction?, bad fuel.

But have you burned it in a truck with a DPF?? My mileage could also be improving because of break-in, since I just passed 7k miles.

I burn it in he wife's VW and have no problems. Mileage is still at 30-33 MPG in the city.. Definetly a lot less smoke.

You might have convinced me about bad fuel, but both vehicles are running on the same fuel, bought at the same time. Also, I know several other people that buy the fuel and don't have issues. Again, they are not running DPF equipped vehicles. This is from a Diesel RV with CAT's and Cummins motors, to Diesel VW Cars, to Diesel Trucks of all breeds.

Does Bio mess with the DPF?? Jury for me is still out. I know I still have a DPF issue with the truck that is NOT Bio related. However, if I go back to B99 and my mileage drops like a rock again - I can say that it effects MY specific truck.

Any improvement, I am liking these DPF delete success stories it is giving me the push I need to drop mine, so let us know how it worked out for you...Josh

What were you getting before the lift? Is your milage hand calculated? Have you re-calibrated the speedo? 10 mpg doesnt sound right, even thought you have lift you should be able to get 15 mpg or better. Why some people get terrible mileage and some people get fantastic mileage I'll never understand, I just hope Im a lucky one when I get mine.
the people getting less mpgs are honest, and the people that are getting 25+ are 7ft tall and a 15" d*ck = liars.

No bs'n, I dropped my DPF and the best i've seen was 17 on the freeway at 70mph. If i had stock tires i'm sure that would be around the 20-21 mark. Big tires and a lift kill the mileage! Stock with lift and tires i was getting 15 freeway. So i did get a couple mpg's from dpf delete and quad!

This topic should be a Poll or something...
James

man, that is horrible. hopefully you don't have to travel much

Just got off the phone with a buddy of mine who has an LMM and says he's getting 6 mpg. towing a gooseneck. Not sure of the weight but he said he's had it back at the dealer and they say they think that in his case it's an injector problem...but he said he thinks they are just fishing for an answer...

Just got off the phone with a buddy of mine who has an LMM and says he's getting 6 mpg. towing a gooseneck. Not sure of the weight but he said he's had it back at the dealer and they say they think that in his case it's an injector problem...but he said he thinks they are just fishing for an answer...
x2. if its not this...its that

You guys are either drive too hard and too fast or drive too much in town. This truck was meant to go on the highway or tow on the highway. I drove from Louisville, KY to St. Louis and got 20 .4 MPG running around 73. Why 73, cause if I slowed down I got worse and if I speed up I got worse. Yes, I was following the On Board average economy, but I have calculated it between every fuel up for over 4k miles and it has been right on every time. I have 12k on it right now. I towed a car and tons of gear to West Virginia last weekend, probably about 7k lbs. and got 13.9. I was satisfied. I dont know why you would buy a truck meant for towing and jack it all up. Of course its not going to get the MPG you want. What truck will? If you want a Dairy Queen Cruiser buy a Gasser and quit complaining! LOL