Tried the alt (was causing power surges) Changed filters, computer and sensors. Runs excellent cold, then after warmup it starts to hunt idle up and down (headlights flicker too) and suddenly shuts off.
Unplugging the oil pressure sensor helped for a short bit it seemed. Thinking about pulling the motor (only 30K on Targetmaster replacement) for a pickup that's currently carbed. Starter is getting swapped out due to old age, but we need to drive it 75 miles to where we'll pull the motor. It would REALLY be nice to put efi in the truck as those Rochester heated compu-carbs sucked (in a bad way)

map or tps.

hell even a water temp cause it.

disconnect the map vac line and see if it smooths back out.

I'd be curious as to whether or not you have a shorted injector or four shutting down the quad drivers in the PCM. The surging is hard to explain, but when those multec injectors fail they often cause a sudden and unexpected stall like you are describing. The fuel injectors are cooled by the fuel so as the engine and fuel warm up it can cause the intermittent short. After things cool down the injectors stop overcurrenting and the quad drivers come back online.

Checking it is easy enough. You just need to ohm each injector or get on the harness connector (not sure where it is on that car) and get the spec for all of them. I don't have any resources handy to look it up for you now.