2 weeks ago, I was up in Sacramento, made it up on only 1/2 tank, 340 miles. Coming back, same thing, and averaged 19. 3mpg at 70-75mph with a/c on. Real cool!! This weekend, towed trailer up to Yosemite, 270 miles each way, Used only 1/2 tank to get there while towing my 6500lb trailer at 60-65mph, average mpg for that trip was 13. 1mpg! I'm still bone stock, and just turned 5000 miles. '06 2500 QC 4x2 with 4. 10's. Each of these drives also involved a few mountain passes. My old '03 2500 4x4 Hemi got a best ever of 16. 1, and towing the same trailer, got 9 mpg, and had to run the Grapevine grade in 2nd gear at 4500 rpm. It would do it, it's that I had to work it harder. This thing, just push a bit more on the go pedal and it's there, still in overdrive. I want some better shocks though, this thing has a SERIOUS case of the bobs and weaves when loaded.