I must be doing somthing wrong
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
I must be doing something wrong
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
I was thinking about new, but...
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
2008 LMM GMC 2500HD Gas Mileage Sucks!
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?!?!
mpg & programmer - not happy with LMM
I purchased an LMM crew cab 4wd in May. The fuel economy was never better than 16 mpg hwy and 13 hwy city. I lifted the truck and put 33" tires on it and hoped that it was a break in issue. My previous truck, an 03 duramax, would average 15 mpg city and up to 22 mpg hwy empty and 14 - 17 mpg hwy towing, varied depending on weight of load from 7000 to 12,000 lbs. I had an edge juice programmer on that truck. I recently put a Bully Dog Power Pup on this truck, really hoping for some mpg results. Being able to correct the speedo was nice, the truck didn't really need that much more power. No matter what the setting that I have the Bully Dog set to, I am averaging right at 13 mpg in town and 17 hwy. I have a very light right foot, so unless milage would increase with a heavy foot, I am probably at about where I'm going to be. Currently the truck has 9400 miles on it. I really miss my 03 and wish I had stayed with it.
Does GM know about the LMM MPG issue?
I lifted my truck with a ProComp 6" and 34" tires in Sept '07. You can see pictures in the TDP Photo Album page.
Interesting that you were able to adjust the speedo as the local GMC dealer said it couldn't be one with Allison transmissions! They also said that I couldn't have the tire pressure sensor set lower than 62PSI. However, a friend of mine with an '08 LMM 3500 said his dealership awas able to lower it in the 50PSI range. Not real happy with the knowledge and willingness to service non-standard features at the dealership.
Was the tuner worth it for performance? Did it make any noticable difference? Why did you select the Bully Dog tuner over another brand?
I wonder if GM knows about the LMM MPG issue?! I also wonder if this forum and the members of the TDP could use their numbers to communicate the issue and see if GM can tell us why and/or address the problem with some modifications.
It's really sad that in this time of high gas prices and diesel technology promoted as high mileage GM can't at least maintain or better yet increase the MPG of their LMM trucks. Most vehicles from year to year increase their MPG not decrease.
Maybe GM will get the wake up call they need when Toyota producesa 2500/3500 series of trucks with their own diesel! I'm sure their MPG will be high and more than likely the truck features and quality will be superior!
Your the exception to the rule!
How are you calculating your MPG? Using the onboard ECU calculations or actual miles driven / gallons of fuel used? To be honest I don't trust the ECU calculations.
You definitely the exception to the rule.:confused: I'm still getting 10-11 MPG City / 13-14 Hwy, if I'm lucky.;) A friend of mine also has an '08 Chevy 3500 Crew LWB 4x4 that gets similar gas mileage to mine.
I would definitely like to know what the difference is and the secret to obtaining higher gas mileage.:) As I mentioned previously my '02 got MUCH BETTER MPG and I should of held onto it!:mad: