They couldn't find anything wrong with the ignition system.....they tested it quite thoroughly too - dyno, ignition scope, 2 drives, etc. I'm going to eventually change wires, and maybe plugs to see if that helps. Probably the on the side of the valve cover wire setup for extra protection. I may try the water test myself too.

Thanks bob, and everyone.

 

Sorry you didn't pinpoint the problem. It is quite frustrating on these engines.

Intermittent stuff is the worst. One thing that sometimes helps is to disassemble and clean all the ground lugs that are on the passenger-side wheel well. They're usually all corroded since the ground stud they're on goes right thru the wheel well and it's exposed to water and road crap all the time. I take out the stud, too, and clean that also. Marginal grounds can cause all sorts of weird problems, and I believe the ground for the PCM is taken from this point.