I did not want to hi-jack the 23 mpg thread but I find these milage reports shocking.
I bought my truck just before christmas 04. To the best of my knowlege there are no mods. I can not get above 15.8 MPG on my truck. I drive 21.2 miles each way to and from work. I have 2 red lights and primarily drive 50-60 miles per hour. I do not pull anything back and forth. The truck has just under 80 K miles.

What can I do to get the MPG up?

Hey love, I get that mileage around town and when I on it. The highway is between 17-22mpg. When was the last time the fuel filter was changed? What size tires are running? If so is your speedo correct.Could be a few variables.

:ro)

The fuel filter was changed about 5 K miles ago. I am running 285x75Rx16

Love2hunt,

I was getting 17-18 mpg with the stock 265's but since moving up to 285's and recalibrating the speedo with my hypertech I still only get 15 - 16 overall. If you went to 285's without recalibrating you'll need to add 7-8% additional miles to the OD.

I dont know if there was a calibration done to the odometer. The truck had these tires when I purchased it. Thats something to look into.

Terry

love, yours is ok. thats what i get and others if they will give you a straight answer.

mileage is a funny thing. My highest mileage ever was just over 22mpg on a 2200 mile road trip with 4 of us in the truck and not towing. However I just did a 3000+ trip and averaged just over 16 with a similiar setup. Winter blend makes a big difference in my area, however being in Texas I doubt you have blended. You could try a different fuel spot to see if it helps, check your tire inflation, etc.

The key to better fuel economy on diesels seems to keep to the RPM's down in the 1700-1900 range(around 60mph).

I second what Victory Red said....the key seems to be in the 1700-1900rpm range.

I will consistently get between 21.5 to 22.5 in that range. Go outside that and it drops fast.

Not sure how trucks report good mileage at 70-80mph.

I am getting 15 with this crappy winter fuel. I got all 8 injectors @ 6 weeks ago and am waiting to see what I get with better fuel. I go 75 - 80 and my RPMs are 2100.

Ben

Not sure how trucks report good mileage at 70-80mph.
they are lying...it drops dramactically at anything above 70....i have 31000 miles in the year i have owned it and the best i got was 17.3 one time on a trip with no load and stayed at 68 mph..i never tow more than 2500lbs and i would love to tow something bigger just to see how bad it would get or if it gets to a point and levels off??

I share your pain I hear these guys saying they get in the 20's and I get pissed. I have 285 tires and my read says right around 15 and I drive between 75-85. In these guys defense my sisters boy friend beats the hell out of his Duramax and while having it floored his read out still reads 16 MPG. I think some of the MPG readouts lie.

Love2hunt, Many people with diesels complain about the mileage, and some report wild swings in the mpg. The biggest varible I've found is that many people don't know how to fill the tank correctly, so they can get correct mileage numbers.

You have to fill the tank all the way to the filler neck, where you can actually see diesel fuel, not foam/suds. Alot of folks will let the pump run till it clicks off and think the tank is full, but it's not because of the foam. Most times I can still put another 2 gallons in after the first click off. This void can cause swings in the mpg calculation depending on how full you get the tank next time.

My truck averages about 15 combined, that'd be 13 city 17 hwy. What sucks is 9.5 mpg towing!
Doug

16 is avg - 20 on highway 70'ish in summer with a tail-wind, and no bass boat. add my 12' work trailer (enclosed) that sticks up above the truck pretty good, with some nice winter blend, and you're hoping for 13ish no matter how you drive:(

I get a consistent 16 mpg in town, with the juice on level 4.

18-19 mpg highway @ 75 mph average speed.

For a big dually, I think it's pretty good.




Kevin:D

I guess that I am in line with everyone else...16 + or - city and 18 to 19 running the Pa turnpike @ 75 mph.

I am installing 285 Mickey Thompson MTX's on the truck in the morning...we shall see what happens next...

I think a lot to do with mileage is keeping your foot out of the throttle and watching your gauges. If you put the display on instant mpg and watch your boost gauge you will see what I mean. I have seen fuel mileage be as low as 3 mpg pulling out hard or as much as 30mpg pulling out easy. The same with 4 lane driving. Keep the boost under 10-12lbs. and fuel mileage will stay in the mid 20's - it just feals like your driving like a papaw! If the boost goes much above 12-15 it really starts to suffer. If you mess around with it some watching your gauges and not romping the throttle to pass people or accelerate I think you can improve mileage and see what I mean. Hope this is helpfull, I just wanted to share my expierence's and try to help people get more mileage out of thier trucks with the outrages fuel price of +$2 a gallon. And to all who have said B.S. on me I have witness's that can back it up and traveled with other trucks that filled up when I did and know my results are no B.S. If you are ever around the east tennesse area look me up and we can go on a trip! Later Nitrous_Nate

I run a spreadsheet for fuel consumption starting at the second tank (5/29/03) until yesterdays fill up and here are the numbers for a totally stock 2003 CC 4x4 SB D/A weighing 7250 lbs: total gallons used to date 1655.21 gallons, average mpg 17.61 for all miles. Highets ever mpg 21.09 (only one time above 20 mpg), lowest ever mpg at 10.62 pulling a 8,000+ pound TT at 70 mph with some hills, 13.13 to 14.45 mpg pulling a 4,000+ pound boat at 70 to 75 mph. Running at the following for normal use: Average mph under normal driving (75 on interstate, 60 on 2 lanes, whatever I can get around town) is in the 17.0 to 19.0 mpg range. Change fuel filters every 8K miles, change dino oil every 4K miles. I find that where I fuel up does affect the milage to a small degree, say 1 mpg at most.

why don"t a few of you try this, when driving down the road, go to your instant mpg, for me that is in liters per 100km, and start at 50mph and work up in small incriments to see what speed your truck is most effeicient at, i have done this a few times and with my setup running between 60 and 65 is not as good as say around the 72mph, with 285 on, it must be lugging the motor at that point, you can pin point where your best mileage is, also keep in mind a truck in stock form is not set up to be effeicent compared to some with aftermarket tunes, running a truck with larger rubber will drop rpm and possibly lug the motor worse without a high tune, their is trucks that run in the 500 miles per tank, i have one, and others do as well, but remember if your in a city and on /off throttle this will not happen, if your running hiway, on cruise you have a chance, to be honest, i have even hit 600miles once in a while, and that is gps counted, as for pulling, i usally pull faster than others, but with a 7000lb trailer it will drop to 14usmpg, into a real heavy wind, take a one more off, but keep in mind, not all of us are lying, like some of you suggest

When I tow a 3000 pound enclosed v-nose trailer at 70MPH, I get 12-13. When I tow a 7000 pound camper at the same speed, I get 11.5-12. I don't think the weight is as much as issue as the wind drag, unless you're in the mountains, at which point the weight becomes THE issue!

yeah yeah yeah who cant get 21 mpg's goin down the interstate at 55 to 60 in a 70. wouldnt it be around that if your at 16 to 1700 rpm's like everybody is saying

My 02lb7 2500 4x4 ext cab averages 17to18 mpg. I have gotten as high as 21mpg in 60 degree weather if I was easy getting on and off the highway, and never went over 2100 during accleration and 2000 on the highway. It is possible.

Just made a round trip to LA, 800 miles or so.

Filled with 47 gals when I got home. 17.1 mpg.

I set cruise on 75, Edge on Level 1, and sat back.

Used to average 14.5 mpg when I was commuting 11 miles to and from work.

Can't complain.

Last week on the interstate from St. Lou to Quad Cities. 70 mph on the way up (cops thick) got 18.9. 80 mph coming back, got 16.8. No mods, 03 D-max 4x4.

grod3ma...your truck came out from factory with 265??? mine came with 245.

I have a spreadsheet tracking fuel mileage (and every cost, maintenance item, insurance, registration, etc) from the time I test drove my truck with 7 miles on it. The last time I updated it lifetime average was around 17.6 or so.

For 4 months I drove it for my 100 mile commute daily up and down the interstate. I found I could even track fuel mileage changes by the wind. I set up a correlation using average daily wind speed and direction with the fuel mileage. Got RSQs in the mid 0.70's. Not bad considering all the variables there are to fuel mileage.

I got 21 mph during a road trip to San Diego (120 miles) when my truck had stock wheels with the juice/attitude and 4" exhaust. Since I got a 4 inch rancho lift and 305's, I cant get above 16.5 while empty. I average 15.5 mph using additives and keeping it light on the gas pedal.

what do i do wrong i get about 13mpg city, highway or 4x4, or even plowing it all only chages to about 1mpg here and there

I get aroud 15 city outskirt driving and 19-21 highway. In cold weather it drops a little.I'm running 2656''s and haven't had recalibration done.

Best I got was 20.4mpg driving like a granny. Stock tires and no programmers. Just the 4inch exhaust and tonneau cover. With the Edge on level 1 and the predator 40hp tune installed driving like a granny (except for an occasional edge level bump to make smoke) I get 19.5mpg. Driving like a granny means I go 65mph on freeway and easy accel. around town. When I just drive like I stole it I get around 15mpg (edge level 3 and hammer down).

I usually avg 18 mpg with 50/50 hwy/city driving. Truck is stock and I run additives. Running the A/C (most of the time here) seems to pull the mpg down. Bucking high winds also knock mpg down.

you guys are all forgetting one thing checking -cleaning -or replacing your air filter if its dirty youer milage will go down

I am into the throttle alot, 80-90 mph mostly on the highway. I get about 14-15.

What are the guys with the 6.0 litre gas motors getting?

I did not want to hi-jack the 23 mpg thread but I find these milage reports shocking.
I bought my truck just before christmas 04. To the best of my knowlege there are no mods. I can not get above 15.8 MPG on my truck. I drive 21.2 miles each way to and from work. I have 2 red lights and primarily drive 50-60 miles per hour. I do not pull anything back and forth. The truck has just under 80 K miles.

What can I do to get the MPG up?

I get about the same...... don't feel bad.

Lifetime average = 21.09 mpg. (36,914 miles / 1750.521 gallons)
Best tank = 23.71 mpg
Worst tank = 19.02 mpg

No towing, 6-speed manual, bone stock with factory Bridgestone 245's.
About 75% highway at 60 mph - 70 mph and 25% city driving.

In my humble opinion, the biggest factors that decrease MPG include: automatic transmission, oversized tires and driving over 70 mph.

It seems to be that every truck differs. My dad's Duramax, fully loaded with tools in the back end gets 16.5 mpg, with stop signs and many job sites to travel to. When traveling on the highway with the same weight, he gets about 19.5. Drop out the tools, travel the highway, he gets up to 21mpg. And that's calculated through mileage and fuel consumption. The computer is pretty accurate in his.

over the last 80,000+ miles we've kept a log on every tank of fuel and everything else that has gone into our '02 3500 ... from this log have learned the following with Hot Juice run in Level 1:


she consistently gets just over 2 mpg better on summer fuel
driving to work (50% country 55 mph, and 50% Raleigh city traffic) she'll get 16 +\- .5 mpg
interstate crusing (non towing) on pretty much level roads she hit 19+ at 55 mph, drops steadly as speed is increased to where at 70 she goes back to 16 +\- .5 mpg
weight hauled (not towed) has far less negative affect on her mileage than speed
towing any trailer lowers mileage and the heavier the trailer the lower she goes ... we last summer towed a 33' heavy TT of 10,095 miles from coast to coast and border states to border states ... approximately 8,000 miles towing and the rest running around ... averaged 12.5 for the entire trip ... towing alone averaged just under 11 mpg
when towing a heavy trailer, a head wind can really have a negative impact on mileage, have gotten down in the 8-9 mpg range
a tail wind is a wonderful thing!
really doubt any of the above will come as a shock to anyone who drives on of these trucks

Jim

I get 20 to 21 on fairly level roads, warm weather, 65 MPH, no load. I do have a tonneau cover on the box. Stock 3.73 rear and 245 tires and run 60 front and 50 rear unloaded.

It's easy to get different MPG if you are not very careful in duplicating the exact conditions! One of the common things done is to fill the tank to the last drop and then next fill stop at the first foam caused pump click off at the tank! That will improve your mileage because you've put a few gallons less in the refill! That's why testing is done in "controlled conditions"! My belief is that around 18 MPG without towing weight is about what you should expect, and about 11 to 13 with a 30' trailer! I got 29 MPG with a Cummins diesel once going from Reno to Los Angeles along the Pacific coast! Downhill to Sacramento and then 50 MPH along the coast! It never happened again! See what I mean!

It's easy to get different MPG if you are not very careful in duplicating the exact conditions! One of the common things done is to fill the tank to the last drop and then next fill stop at the first foam caused pump click off at the tank! That will improve your mileage because you've put a few gallons less in the refill! That's why testing is done in "controlled conditions"! ...
That is why you keep a running total in a spreadsheet. If you put a little less in one time, that instance of mileage will be a little higher, but the next time you will make up for it. Thus, the average works out all the same. My dad annoys the heck out of me when fueling his car as he will sit there for 10 minutes trying to get the last drop in the tank so he can calculate his mileage. If you just keep a running total, you never have to worry about that last quart or two upsetting your calculations.

I just got back from a trip to Kentucky. I set the cruise at 70. I have the TTS extreme so the lowest I could set it was 80hp(tow). With me and one other passenger and maybe 100lbs. of luggage I got a hand calculated 21.5mpg. 2100rpm@70mph. Can't complain about that especially since it is 80hp over stock.

Thought I'd sound off here too. My '03 has just over 36K on it now. Lifetime MGP is 17.29 with the high at 22.3 and the low 10.9. (Dash readout was 24.2 high and 12.3 low). Highest MPG streak was 22.0, 20.0 and 19.7 driving 1340 miles at 68 MPH in one day hauling the back 1/2 of a Ford Tractor in the bed. And yes, that was one LONG day! Left at 03:00 and got back at 02:30.

Air pressure, tire size, load, traffic, aero all have an affect on MPG. I keep the tires at the max psi, stock 245 tires, live were there is little traffic and have a bed cover. BUT, the largest impact to MPG is driving style. I drive like a little old lady!

The other day the dash was telling me the truck was averaging 19.3 MPG with over 350 miles on the tank. My wife took the truck to town (30mile round trip) so I could change her oil. When she got back it was down to 18.9 MPG average. Now I know who the lead foot of the family is!


As they say, Your Milage May Vary!
John Bud

[QUOTE=love2hunt]I did not want to hi-jack the 23 mpg thread but I find these milage reports shocking.
I bought my truck just before christmas 04. To the best of my knowlege there are no mods. I can not get above 15.8 MPG on my truck. I drive 21.2 miles each way to and from work. I have 2 red lights and primarily drive 50-60 miles per hour. I do not pull anything back and forth. The truck has just under 80 K miles.

What can I do to get the MPG up?

I'm running the stock bridgestones that came with my truck (Lt245R16) and I get an honest 19 miles to the gallon of fuel. When I don't keep the air pressure to around 65#, the mileage will dip down to 18MPG's. I get my best results with Love's fuel, however. Hope this helps.

Here's a theory, at least for those with Allisons. Our transmissions are adoptive learning devices. So for those of us who are featherfoots with long gentle drives, we get upshifts early and this contributes even more to our good MPG.

For those with short drives and who get their foot more into it, the transmission is looking to optimize itself for this kind of driving, and this contributes to the lesser MPG, in addition to the fact that the engine is spending less of its time at optimal temperature and conditions to deliver its best MPG.

I have a 05 Duramax with 6" RCD Lift and 35 open country MT's on 20" wheels and according to my truck I average 10.7 miles per gallon. I am probably in it harder than most people. I also just put the edge w/ attitude in and usually run it on level 5. I had an 03 that got alot better mileage. Not to impressed with the new one almost wish I had kept the 03. I have decide to stop trying to calculate the fuel mileage because it would just piss me off and I probably won't change how I drive. Do you think that if I run my edge on level 1 it would help and if I got rid of the CAT on the exhaust?

Also far off would my 35" tires make my odometer as far as the MPG average thing says? If it says 10.7 what is it really?

The published diameter of 245/75-16 tires is about 30.5 inches.

So 35 inches is about 15% larger. So where a 245 would go a mile, a 35 inch tire would go 1.15 miles.

So you would have to increase 10.7 by 15%. That gives you a whoppping 12.3 mpg.

I apprecate all of the responses. I have checked the tire pressure, changed air filter (stock) kept my rpms under 2K. I have run 2 tanks of fuel through and still get less than 16 MPG. I am not pulling anything. I have a three hole dog kennel that sets in the bed near the cab that weighs about 150 lbs.

One thing I have notices is that the tranny seems to take forever to shift. No matter how hard or easy I drive, the shift points in MPH seem to be the same. Has anyone else noticed this?

Terry

thier are a lot of facters on milage in how you drive i get better milage than my wife dose on a trip we just drive different or how you take off from a stop light or check youer air filter if its starving for air itll use more fuel every one seems to forget about that

do you have it in tow mode

do you have it in tow mode
I do have tow mode but that is not engaged

I tow around 4000lbs just about every weekend. I pull a tandem cargo which is like flying a kite back there. My best MPG so far has been 17.9 but that was
towing at 60 mph in very calm night air. I have found out like the other folks here is that anything over 60 with this particular axel ratio I have turns into
15-16 mpg real quick. When I run without trailer the absolute best I have ever gotten is 19.6 mpg. Still better than a Power Joke.