This afternoon I drove around half of Cape Cod doing necessary family things and picking up parts. No single trip was more than 30 minutes but it was probably 90 minutes of driving total, the car ran fine. I filled up on gas and left the cap only barely snug in case a tank vacuum was the problem.
The parts I got are a TPS, fuel pump, coil, and ignition module. When I could finally get to work on the car, it was after dark in a gravel driveway of our house here. I started with the ignition stuff as that is easiest. Once I pulled the (nearly new) distributor cap off, I saw a bit of something in the center of the rotor that didn't belong. Looking deeper, the center button of the distributor had broken in half and the lower half had fallen into the center of the rotor and has clearly been rattling around in there for a while. Fortunately the only close FLAPS had the distributor cap in stock and didn't close until 9PM, this is one time to thank goodness for common GM parts, the cap was there and $18. Here is the new center button and the one I removed in pieces:
So, this all makes sense to me. If the center button was in half, the coil was having to work extra hard to make enough spark to bridge that gap, I can see how it would overheat and have weak ass spark that wouldn't be able to ignite with heavier throttle. After replacement the car seemed to run smoother. I leave for the rally at about 4:45 AM tomorrow to pick up my friend and get to the start. I have the spare fuel pump and TPS in the car still in case they are needed.
Chris from 3 Pedal Mafia