loose of power and bad mileage

My neighbor has the same complaint about his F-350. He bought it new with the assumption that later improvements (computer flashes) would enable his truck to get better mileage and more power, but it never came true. He says that he currently gets about 8 or 9mpg and he travels to various parts of the state on a regular basis. I can't help but feel bad for the guy.

my powerstroke is the same way now after getting the dealer to flash it, horrible milage too, your best bet is to buy a chip and turn up the hp a bit ( not to the top), and not the cheapest chip you and find, its prob going to cost you 500+ you need to find one with a egt built into it so you dont nuke your engine ... remember you pay to play

the 6.0L isn't the best engine that ford/international have given to the consumers in a while, I personally think it was a mistake to drop the displacement and design changes. the best one was the turbo 7.3, thing was practically bullet proof, International just gave Ford a retuned version of the school bus and transport truck diesel 7.3.

I have a Ford Ford F 250 I had in new have 310.000 miles on it I am getting shity gas mileage what can I do help me thank you