I have f-350 2wd, f-550 4wd, and a f-650 with a cummins for work. all seem to get around 10 mpg under almost all loaded conditions. I am 30 going on 70, needless to say i drive extremely conservatively. my f-650 with a 5.9 cummins will get about 12 mpg driving 5 mph below the speed limit. Keep...