My gut is still telling me there is an issue with the alternator. But I had it tested twice by 2 different shops and they said it was good. The unit is a Powermaster 90 amp built out of the old round back case. A buddy had one on his car that failed him on the road 3 times and the alternator still tested good. He replaced the alternator with a new one and never had a problem again. I believe the spike fried the tachometer.