The vehicle began with problems that seemed related to the battery. it jerks when accelerating between 40 and 60 mph. problem codes keep changing and check engine light remains on. first codes indicated cam/crank shaft, then misfiring, then crankshaft, even after cam and crank shaft sensors were replaced. jerking continues to worsen. ford 'claims' the code was not in their system, initially. problem seems to be causing many things at once to go bad: battery, compressor, fuel getting to engine, etc. problems have occurred over several months. *tr