06 with 1200. miles. Sometimes I can get 12.7 around town, driving like a old fart but not my style. Most of the time 11.0 like everyone else.

you know if I baby it around I can almost get 10 mpg. I guess its the racer out of me that wants to race other big trucks.,.......LOL

I usually say I get around 11 GALLONS to the mile. LOL

Averaging about 11.8 at 5,000+ miles. Just installed Corsa Sport exhaust today. Wonder what I'll get now?

Albie, Ive got 38s, exhaust and a volant intake and I am barely gettin 9.9! Programmers on its way and that should help a little more! You!

12.5 on our 2004. Both 2003's were a tick over 11.0. Not sure why since driving habits and routes were exactly the same. Did they do something in 2004 to make it better?

2003 H2 35K Miles, Superchip, AirRaid, Borla Exh w/ resonators chopped off and straight dual 4" pipe from the muffler back, Stock tires and rims. Getting 8-9mpg city, 18-20 on the freeway if I avg 80-90mph. Go to and from SanDiego and Northern Cal at 80-100mph when I can, even with the trans in down shift mode because the accelerator pressed so far, and do the math on the calculator at the gas station, and it is religiously 18-20 mpg. Even pulling 2000 lbs of Jet Skiis at 70-75mph I still get 15mpg. Go Figure. I DO drive a bit aggressive in the city (I grew up driving in Boston) But on the freeway, I think it's because of the lack of backpressure with the resonators gone, the motor breathes real nice on the freeway. The truck LOVES to get out and run!

12.0 with highway and off roading... not much city driving except freeways. Better then I thought when I bought it. Just as good as a whole lot of trucks and SUV'. SO THERE

Sure shows the physics of the problem. Our Denali gets 15 average and up to 19 on the highway. Barn door theory proven.