OOIDA's most recent issue of " Land Line " magazine has an article about a driver that had trouble with poor fuel mileage then noticed the high temperature of the fuel he was regularly buying at Flying J . Changing to another fuel source increased his fuel mileage . About a month ago I had a problem with a Flying J manager when I used a credit card at the truck pumps and noticed I was being charged 4 cents a gallon more at the truck pump than I would have paid at the RV pump . I tried to change the transaction to cash but the manager refused to give me a lower price . I quit buying fuel at Flying J . My fuel milage loaded increased 2.5 mpg loaded . OOIDA investigated fuel temps at fuel stops . Fuel at Flying J averaged 30 degrees warmer than fuel at other fuel stops they tested .