My old "spine of steel" ram.. '01 2500 2WD 5.9 got about 17 mpg going the same course for many years, even at 326,*** miles. Both figures, of course, are in the summer time. The old Ram had a bigger tank and could hit 500 miles to a tank if I ran it down. This '13 Ram, I've got 551 miles to a tank, and it's a smaller tank.