Oh, my 300 mile drive to Telluride and back netted me 15 MPG, which is pretty good for a 3/4 ton 6.0 truck! My '02 averaged 12 MPG. I think much of that mileage was due to the roads down & back, 55 - 65 MPH and no freeway driving. I'm hoping the 6 speed trans is part of that too, keeping the engine from revving too high and consuming much fuel. We will see this upcoming week, I'll be putting 400-500 miles on it with half of that being freeway driving.