larryd.meeks

I have a Cummins ISM (400 hp) with the Allison 3000 MH transmission. I drive at 1650 rpm (that is about 62mph). I consistently get 6.5 mpg. I have done a few things such as change out the muffler to a straight through turbo type and even put a chip on the engine, still 6.5. I have decided this is all I will ever get. You guys that claim higher mpg's consider yourself very lucky!!! I go down the road pulling a Camry on a dolly and just over 38500 lbs GVW.