F250 PSD vs F150 5.0L towing 9k lbs

there are a few issues here, first and biggest these two always get brand new trucks that are not broken in from the factories for there tests. anyone who had owned a new powerstroke or most diesels for that matter know that they get way better milage after 30000 miles of break in. second it was a short run and probably heavy with some stop and go to start, third they are driving 70 mph, and 4th its a bumper tow with a big gap between the truck and trailer which will have more air drag. when I went from a 9000lb bumper pull to a 13000 5th I actualy increased my milage by 1.8mpg. I get 13.3 towing my fithwheel at 60mph, at 50-55 I get better, I think the best I got was 14.6 (these are the us numbers) at 70-75 mph that drops to about 10.7mpg.

want better milage, slow down, I know its hard ;)

Steve