I drive a '00 F-250 V10 5speed (yes 5, not 6) 2WD with 3.73 gears. Its an extended cab long bed with 183,000 on the clock. My daily commute is about 55 miles with speed limits anywhere between 25 and 60 MPH. I've been checking it pretty religiously, and its resting at a pretty consistent 13MPG...