I just bought a 2008 F-350 long bed, extended cab, 4x4, 5.4, automatic, 4:10 limited slip, single rear wheel. It's getting 12 to 13 around town and 14+ on the highway with cruise set at 75mph. Mileage was hand calculated and the computer is giving similar results. Engine is still fairly new and hopefully mileage will continue to improve after a few thousand miles.