my 88' stang has been modded to be mass air before i bought it..it ran fine than after change out the spark plugs and wires coil and ignition module and now the coil now keeps arcing and is missing through normal aceleration. i am trying to trouble shoot it and cant seem to find the problem with the car..i would be highly appreciative with anyones guesses to what may be the problems...thank you very much for your time.