I have a 2008 2500 hd. I get 11.3 to 13.5 depending on temperture and humidity around town. On the highway I get consistant 18-19 with highs as much as 23.7. While driving through a rain storm I went fron 19.6 to 24.0 on the Ohio turnpike. When the rain stopped so did the 24.0 back to 19.6

 

21 Unloaded highway, 13-14 pulling mastercraft, 15-16 City...after trans build. TC was shot was getting 17-18 unloaded on highway, and 11-12 city.


08LMM, EGR Blocked, DPF Deleted, Cat ran away, PPE Stage 5 trans, Edge, Banks CAI RP Gear OIL

 

I have an 2007.5 GMC Z71 4 x 4 with 20" rims, cab height camper shell and at least 6" lift. I bought the truck used set up this way. My mileage is nothing like anybody else's I've read on the forum. I get around 8mpg in the city and 10 tops on the highway not towing, towing on the highway I get between 6 - 8 mpg's (19" toyhauler trailer). Does any one have legal suggestions that can help me increase my mileage.

Thanks,
Charles

 

if you want legal you can try using water meth injection and running a banks tuner imo

 

the big wheels and lift are not helping your mileage either, you want optimal mileage get the truck to stock height or lower

 

Thanks for the tip, I've been told this already. I know looking cool doesn't get good mileage so I may have to resort to stock suspension and wheels.

 

do they sell efi live tuned ecm's for lmm? that would be the way to go.... just save the stock ecm for warranty work.

 

Yep just gota know where to look, duramaxtuner sells them, im sure some of the vendors here do as wel

 

Thanks guys for your suggestions. Now I just gotta figure out where the money's coming from to make the changes required.

 

I'd like to thank those of you who took the time to give me suggestions to my mileage problem. I found that by driving with my Allison Transmission in Tow Haul in the city and on the hwy without the trailer that I get better mileage. The only trip I've taken and used this suggestion I got 17 mpg on the freeway instead of 10. The same suggestion for the Tow Haul also mentioned when towing do not use the Tow Haul but run the 6 speed transmission in manual 5 (haven't tried this with my trailer yet so I don't know the out come).

Thanks again everyone