Robert: Did any of these comments help? Since you started the thread, want to make sure the issue is resolved. If it is not, chime in w/ update, and people will try to assist.
Paul: How old are the wires on the motor? If original, try replacing them. Mine were shorting through the "boots" on the coil end. Depending what you are driving, you may be able to test this by pulling wires from your vehicle, at least long enough to see if it makes a difference. If it does, you can buy a set of auto wires from your local parts store, for less than JD will sell them. I think mine were for a 4cyl Ford, and it cured the problem.