http://www.fuelly.com/car/chevrolet...id=125&bodytype_id=&submodel_id=On the home page select browse vehicles. Then input engine and options to get a survey.
I had a 2005 with 5.3, and I got 15 mpg, in rural/highway conditions. My best friend has a 2013, and he said a bit less, but he drives pretty aggressive.
I put 100K on mine, and it was always at the shop. Beside being expensive to maintain it was a nice commuter truck.
I was in the same boat with my 04 GMC 4x4. Beautiful comfortable truck, but many problems: I'll list as many as I can remember:
1. Front diff needed to be rebuilt soon after I bought it. Good thing it was under an extended warranty.
2. Transmission needed to be rebuilt. 4l60E is very weak and troublesome.
3. Transfer case started weaping, which is a very common problem in the autotrack type transfer case.
4. G80 locker went tits up at 111,000 miles.
5. Transfer case actuator went bad at 120,000 miles.
Gas mileage was worse than my wife's '99 suburban with the 5.7 litre engine. I was lucky to see 18 MPG with the 04 GMC sierra 4x4 with the LS1 5.3 on the freeway... When I got rid of the truck, the engine was still running like a top with no oil leaks and no oil consumption within its 5,000 mile oil change intervals. The engine was bulletproof, but the rest of the drive train sucked balls.....
