Out of the blue SP started autoplunging occasionally. I was sure it was the shooter lane switch or maybe the pinball bouncing on the switch when fired up to the plunger but the switch works as it should. I though maybe a switch on the rail was not working but they all checked out. The ball doesn't even have to touch the shooter lane switch for the autoplunger to fire. Sometimes it works right 2 out of 3 balls. Sometimes it will play a whole game by itself after pushing start. Any suggestions?