Hope we can help you figure this out soon. Maybe next time it acts up unhook the wire to the coil and the starter. Hook the meter to the coil power supply. Turn the key to start and see what you have for voltage. Make sure the starter wire is not touching anything. Then take a jumper wire and supply power to the small starter wire (key in the run position) and see if there is a difference. How is your distributor wired up? Can you tell if it is wired directly to the key switch?