LMM Fuel Economy

[jsracing6]

i get around 17 empty on highway and 7-9 towing 7000# 28' enclosed car trailer

[Dakster]

I hope to see the 17 mpg empty. I got 15 on the way home tonight from the dealer... 2007 3500 CC Diesel, 4x4 Long Bed, SRW.

[jharden1]

Enroute to work I reset the avg. fuel mileage on the DIC just to see what numbers would come out. 35 miles of mostly level at 70 mph. 21.3 on the DIC.

[larryh1]

9,000 miles, I have not seen anything above 14.9 - empty. 10 MPG towing 30ft trailer. I have been to dealer twice now. No help there - they have been good about it, but no help. They suggested a programer. I have installed a KN filter and superchip, runing in safe tow. I was told safe tow will offer the best mileage. No change. I checked tire pressure, all is good. I love this truck but fuel prices are going to make me park it.
(I'm not comparing, but my son has the Ford 7.3 we just drove to NM. About 950 miles - towing a small trailer about 1,000 lbs. Got 29 MPG!!! I wouldn't have belived it if I didn't see it with my own eyes!!!)

Any suggestions would be greatly appreciated.

thanks
Larry

[Dakster]

Larryh1,

So far I am on par with you.... 29 MPG on a 7.3 is incredible, that has to be a 2wd truck? I could get 22-24 with a 2wd 6.0 excursion (when it actually ran)..

[larryh1]

Dakster

That was doing 70 mph (cruise control), flat level driving with an occasional mountain range. I was enjoying ragging him about how much more comfortable my chevy was compared to his ford, until we figured his mpg. I kept quiet after that.

I haven't given up yet. I will be happy with 17/19 empty highway,and 11/12 towing. I am talking to a diesel shop for some less expensive ideas. I'm not going to spend thousands of dollars to get 2 mpg more. I also keep checking this board for any ideas.

Larry

[Dakster]

I hear you... Chevy's definetly have better comfort features... My 2007 Suburban was getting 9-10 in the city and 14-15 on the highway empty/not towing. I'll be happy with 12 in the city and 17 on the highway empty. (20% better fuel mileage). I have nowhere to go but up! I'll get a better handle on what to expect for fuel economy in two months when I drive to tennessee and back.

You can rag on the new 6.4 Ford's, they get horrific mileage. A buddy of mine traded his 2006 Dodge for a new ford (both are dually's) and gets HALF (6 mpg!) of what the dodge got while towing his car to the races. He doesn't know if he can afford the new Ford because of fuel costs! This new DPF/regen requiement doesn't seem to be very MPG friendly.

[1stDiesel]

I have run 3 tanks of fuel through my new 2007. It is the 2500 crewcab. I filled up today and found I got 14.6 MPG on routine and city driving. I was hoping for better, will it get better? Going camping this weekend will let you all know how that goes pulling my trailer...

[axisrobotics]

I have a new 2007 GMC 2500HD duramax diesel. With 3 tanks of gas and 1,127 miles on the odometer, the computer shows 18.1 mpg. I have manually calculated it to 17.86 mpg.

Mostly short 20 mile runs with some daily city traffic and aprox 125 miles pulling a 3,000# trailer.

[diegojp]

So what's the secret to all this amazing mileage I am reading about? I am on my 4th tank of fuel and average about 13 mpg city/highway. I drive about 65 on the freeway and my driving is pretty evenly split between city and highway.
Granted I have the 4x4 and usually have to drive with the AC on but I can't imagine those factors make a huge difference. Am I missing something? TIA

[Albee]

06 LLY 4X4 Dooley. Best seen on freeway ever is 16.3. Around town, 12-13 mpg. Pulling 17-18K over hill and dale 8-9 mpg. Not as good as my 02 LB7 2500HD. Best was just over 20 hwy. and got around 15-16 in town. This LLY is not near as economical. But she runs good.

[axisrobotics]

The best I can tell the dual zone a/c stays on all the time. I get about 1.1-1.3 better mileage with the compressor button turned off.

[winmck]

3 tanks - mostly highway - averaging 16.5 mpg on the DIC

[SDWA]

All this talk makes me want to keep my 2002 LB7, no matter what it costs to keep it running! I've consistently gotten 18-19 mpg from day one, peaked at 21 in the first year, on a full-to-empty flat road trip...

Scott

[diegojp]

Just thought I would post an update. I did a 5 day offroading trip last week and averaged 9 MPG(DIC and calculated) towing over 14,000# on freeways an mountain roads. Not too shabby, IMO.
Unloaded my truck is still pretty consistantly getting just over 13 MPG with mostly city(60%) driving. Unloaded on the freeway today, I was able to get 19 MPG over about 100 miles at 69 MPH. That dropped down to 14.5 shotrly after I got off the freeway, however.

[jharden1]

17.6 DIC on the last 1600 miles. Mixed miles. 7500 miles on the truck.

[craigth]

I am VERY unhapp with my LMM 2008 GMC 2500HD Crewcab SWB 4WD gas mileage!! My '02 of the same model got 100 miles to the tank better than the '08! I'm really surprised that 6 model years later and with the fuel price/supply issues that GM could not at least maintain the mileage of my '02 or make it better! I wonder if a power programmer would help?!?!

[Stlheadake]

Craig, I would be careful putting a programmer in that truck. From what I understand, you run the risk of clogging the DPF with a programmer. Not a cheap fix for more mileage.

I too have been in the 'hunt' for better mileage. My '06 doesn't do too bad 15 city and as high as 18-19 hwy (about 70mph). Still I feel it could/should do better.

[snowsporter]

I had just purchased a dmax with the lmm engine. at just over 60 mph i am averaging almost 23 mpg highway. combination so far i am averaging around 17 mpg. first diesel and so far am impressed. i had just traded an 8.1 for the dmax that averaged highway 8 mpg, city around 6 mpg and towing 10k trailer 5mpg.

[kwtriton]

Purchased an.. 07 NBS 4x4 4dr. short bed. Traded 01 xt-cab 4x4 D-Max w/300,000. The 01 constantly got 19 mpg on the hwy, New 07 is kind of strange and I am sure it has to do with the power curve. At 65 mph reset avg mpg truck gets about 16.5 mpg. run it up to 75 mph truck gets 21.8 to 22 mpg. I thought it was a fluke, but I have checked it several times and get the same results. Avg overall it has been running around 17.8 to 18.2 mpg, Truck now has 10,000 (+) and I am very satiisfied w/mpg.