With the purple wire connected to the + side of the coil, I get 12.5v and starts. Other times and intermittent, It shows 10.8v at + side of coil (no start). Remove the amplifier (purple) wire from the + side, back to 12.6v, touch the amp wire back to the + side, drops to 10.8v and can hear a spark inside the distributor cap. This comes and goes. Guessing the amp is bad, but there is no way to test them?
