The main issue I had with ball launching on my Baywatch seemed to be a basic design flaw.
The "high rise" mounted shooter coil bracket has the shooter lane switch mounted to the coil bracket. I had Very regular issues with this switch failing. Sometimes from broken a wire, other times the switch simply giving out. Best stretch I got out of a repair was a month at best.
Eventually I figured that the crazy vibes associated with this shocking flexible bracket were probably the root cause, so I mounted the switch on a bracket to the playfield instead, the way any smart engineering design would have it. Haven't had a shooter switch failure in almost 2 years now, around 1000 plays.
Also I just probly jinxed the good run by saying it!