I am new to this forum but, have a lot of years with mods and testing in different vehicles. Right now I have a 1997 Toyota Corolla that is getting between 34 -38 mpg. I just bought a 2005 F250 Super Duty with the 6.0 liter turbo diesel. Right now I am able to maintain around 16 -20 mpg on it. I am hoping to up that to 20 -25 mpg.