I did a 1600 mile trip through washington and set the cruise on all speed limits. Trying to be light on the throttle. I tried to make it as accurate as I could without having a the top gauge. I would let the fuel light come on each time for fill up so I calculated it to be approx. 24 gallons from the fuel light. I was hitting 485-500 miles per tank, so that would be approx. 20.5 mpg. Some of this was at 5000 feet some was at 500. Im sure elevation matters. More 02 through intake for more efficiancy. If guys are at sea level then see 24 mpg a possoibilty because especially if the have stock tire size, I am running 35 toyos.