Agreed with Dave on the sub standard part deal.
If you've ever popped your hood on a super humid night, you will see tons of condensation/water vapor covering everything. This combined with water that gets past the hood/cowl seal when you wash your car and or drive in a rain storm, will eventually soak into the CCCI sandwich. That piddly little gasket that comes with the parts, doesn't last forever and does not play well with water. This and super uber heat cycles underhood for 20 years, especially during those 90+ degree days will eventually lead to Coil or Ignition Module degradation and or failure. One trick I use whenever I wash my car, whether at home or at a manual car wash (You know the drill, stop at car wash to spray off the bugs before putting her back in the garage after a night out messing around on the streets) is to always keep a towel in the trunk. Pop the hood, and double fold the towel so that it covers the back of the engine/wiring harness/C3I assembly. Even with the hood/cowl weather strip seal, you would be surprised just how wet that towel gets.
Recently, some have reported the volcano effect of having the insulation goop boil out of the ignition module and make a big mess. Shortly there after it goes POOF!! I have seen this happen many times over the years on friends cars. I even had one just start to do it, but I caught it in time. It was my original one on my old grey car. My personal maintenance SOP is to change out the coil and module every 2-3 years, depending on how many times I race the car, and or miles I put on the car. I also invested in one of Caspers Electronics' coil pack testers. Best $99.00 I ever spent on my Buick specific diagnostic tool kit.
Glad you got it figured out. When I first started reading it, I was thinking it sounded like symptoms of C3I malfunction/failure.
Patrick
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