quick test, wait till night fall, the dead of night when its really dark. open your hood start your car....... make sure you are not in enclosed garage.. look at all your spark plug wires and see if they are arcing anywhere. raise the rpms up to the level the car stutters, and see if you can see any arcing. The wires should not be sparking or showing any glow whatsoever. Its a quick test and you dont even have to get your hands dirty