With my 96 Chevy C/K 1500 4.3 Vortec 5 speed I get a consistant 21 mpg. But like Joker sez I drive like an old man I guess its because I am an old man. Doesn't matter if the topper is on or off mileage is the same. I have found if you keep your foot out of the carburetor (or is it the injectors?) and shift smoothly the mileage is the same. Now pulling a camper its a different story. Mileage drops to 14-16 because I can't get out of 4th gear because the rear end gearing is so high and the camper is quite heavy, My .02. Also when analyzing MPG always deduct at least 10% from what anyone tells you because you have to allow for the bull$h%t factor. Weeds
