Wife and I drove the round trip from Phoenix to Tucson on Monday. Fueled at the Flying J on I-10 in Eloy for $1.61 per gallon. Mileage from Flying J, driving in Tucson, and then refilling at the J on the return to Phoenix was 18.6 mpg. That mileage was with the ac on and four people in the truck. Wife drove about three-fourths of the trip and she has a heavy foot.