A friend told me that he towed a piece of equipment that weighed 2500 pounds. It was not aerodynamic at all. He got 8.5 mpg running 60 mph.
He has a 2012 Ford Eco Boost.
Resistance factor increases with speed. Yes, I read the f150 forum and the towing group has come to a conclusion as I mentioned about ecoboosts, torque and final drive ratio. the higher ratios keep it in boost mode burning more gas. they suggest the 3:55 ratio is better for that engine.
Just to reiterate I check overall mileage at fill ups using the odometer; however, I wanted to find out what a forum member mentioned, that he could save 20% by slowing down. By using the computer I was able to determine that such a thing is potentially possible as it read a 1 mpg difference between 5 mph increments. The computer may be less accurate but not severely off on difference. What is tricky is if I reset it, drive down the highway for 10 miles getting 21mpg then get gas when I used a half tank driving around town. When I check the mileage I get per se 17 mpg and wonder why. My 2010 VW tdi computer was very accurate when checking against odometer reading and fill ups.