Im considering getting a ford f250 or f350 to pull a fully loaded 7x16 enclosed tandem axel trailer. Right now I have a 07 GMC sierra 1500 with the flex fuel engine and the gas mileage is killing me. Do yall think I will get that much better mpg with the diesel. If I had to guess i would say im proab getting between 7-10 mpg with the sierra. I would also like the heavier truck for the bigger payload.