So I have an 02 mountaineer 4.6 its got almost 200k on it and the gas milage sucks, I have a remanufactured transmission and new intake, new plugs ,filters fluids, it lacks power that it once had and mpg are 14 at best right now its 13.6 my question is should a start hunting for an engine? When I pulled the plugs 2 were black with oil but I haven't done a compression test yet.