Have an 08 2500 hd 6.0L 3.73 tows great, rides great, very adequate power......HORRIBLE MILEAGE!!!!!! Same empty, loaded, whatever just plain bad. 10 mpg on a good day in a tailwind downhill! But works great, owes me nothing and keeps me legal with the inline 4, or sled deck etc.
Last truck was an 08 sierra Denali had a custom tune, lierally got over 21 mpg anytime/everytime empty and 15-17 mpg pulling.
Downside, low ground clearence and persoanally am tired of the awd push steer, and never really knowing what the road traction really was ....as you always had all that was available untill you didnt.
Loved the truck, sold it to my father. He now loves it!
Curent truck is a 2011 sierra slt crew,max trailer with 6.2, 3" leveling kit, 285's, 4.10 geared, stock tune. LOVE THIS TRUCK!!!!!
Getting 17-18 mpg empty and better than 14 pulling. And it does it all!
And in 2wd it lays rubber like a vette! Lotsa fun!.......needs a custom tune though i think, mileage may improve... But i am pushing more air than the denali by around 4 inches or so.
My choice max trailer 6.2.
skier
Ps.. Have a buddy who sold his f250 stock diesel after he couldnt keep up to the Denali towing uphill through BC....and mileage was was pennies better in gasser too! He's now driving an escalade.