Need some ideas please... I'm pulling my hair out! Ever since last summer, my 03 mustang 3.8L manual has been running rough and hesitating on acceleration. It's noticeable in 1st bucking at about 1700RPM, bucks if I take off from 2nd gear, in 5th bucks at very low RPMs when pressing gas decently. Runs fine and smooth in high RPMs. Here is the history: July 09: platinum plugs, wires, fuel injector cleaner, fuel filter, radiator hoses, clutch, flywheel no difference October 09: alternator, camshaft sensor, crankshaft sensor, ignition coil pack got worse, threw code for coil pack, put old coil pack back on. wouldn't even idle, had to rev it hard to run it at all took to ford dealer, told me pcm failed. they replaced pcm. one day after it was running rough again. took back to ford dealer, threw code #3 misfiring. they replaced #3 after market plug with motocraft plug. ran great. week later, running rough again, same as last summer. January 10: put new motorcraft plugs on, no difference. today: replaced entire air filter assembly including mass air sensor. tried another coil pack from different auto part store, ran worse, put old coil pack back on. running same as last year. what gives?!?!?!?!?!?!