I have gotten as high as 19 mpg hand calculated, 2wd, my HTT with about a 450 hp tune, stock wheels, what I call summer street tread tires (not ATR's) at 75 psi, cruise control at 70, moderate terrain. This is a crew cab, long bed 4x4 truck, no real load, 2 adults, 2 kids, and a full tank of...