I live in Oklahoma and drive a 2003 F-250 with a 6" lift and 33" tires. I make around 10 m. to the gal. pulling a 20 ft. gooseneck trailer. Last year I went to Santa Fe NM and here a couple a weeks ago I went to Virginia. Why do I get better fuel mileage pullin through the mountains than I get pullin in flat oklahoma? Don't know if this makes any sense, but I was wondering if there's an explination.
speed makes alot of difference. my 07 duramax has about an 8mpg difference between 60mph (22.4mpg) and 75mph (14.8mpg). If you like to fly on the flats you will pay at the pump.
mileage difference This might not be of any real value, but the temerature of the actual fuel itself does make a difference ( I'm assuming you are using trusty #2 ) and the time of year ( winter blend ) also is a factor. Beleive it or not, the warmer the fuel the worse off you are. There was a big to do about the temps a while ago, Don't rememeber exactly, but it was an interesting article - in one of the semi publications. Hope this almost helps
