Have seen this happen with bad plug wires and with bad grounds. Coil will give all the charge it can so if their is a short somplace or a break in the wires it will soon overheat the coil and take it out. OHMS test your plug wires and i will bet their is one that is higher than the other and that one will be the cause. Go to your local parts store and just make your own plug wires, get the ends and their wires their. Some places will make them for you, nothing to it.