Only way I got the mileage some of you guys are getting was either downhill, or with a stiff tail wind. W TX where I live is as flat and level as you'll find anywhere, and setting the cruise on 70mph, straight out run on highway, I could get near 18. Bump it up to 75, the speed limit on the interstate highways, and I'd get 16 max. I never reset my miles per gallon calculator over 75kmiles, and it said 13.7 overall combined MPG.
My current Silverado 1500 crew 4x4 gets 21 hwy (same roads), 16 city, overall avg for first 2100 miles is 17.1mpg. I've owned them all when we ran our small fleets in the oil patch.
