2002 Ford E 350. I don't drive 70 mph so can't respond to that. @ as close as I can stay to 62-3 mph 21-23 per gallon. 65 mph drops to around 19-20. Over 2000 lbs and it will drop a little more. I aslo have a 1999 F 250 Super Duty six speed with 4 WD. It has cruise control and I get close to 20...