I got a 94 impala that I just did a tune-up on, and my idle is still rough. I have MSD wires, coil, and AC Delco platinum plugs. I checked my spark plug wires at night and see that all of them have flashing light coming out where they attach to the plugs. So I bought new wires and there still flashing. Im pretty sure the wires arent bad. So im guessing the MSD coil is whats doing it. Can someone help me on this.