Check the switches on sparky. Sounds like something is constantly triggering.

So seems like you need to investigate the optos in front of sparky. You will need to check to make sure the wires are correct, and that the optos themselves are aligned.

Optos detect a switch opening due to the breaking of a beam. If the alignment is off it can be just off enough that the vibration from other things can cause it to go from open to close to open again. The reason I am guessing it is auto launching is that the switch is registering while the ball is in the shooter lane and the game thinks the ball should be in play. Does it give you the ball save animation too?

I think they are pretty far forward, i would start with just the plastics and see if you can get to them.