FWIW, I suspect something electrical. Perhaps something like a PCM ground or similar critical circuit without which the engine cannot run.
I had an 86 TransAm, bought new, It sometimes would...
Probably not unless you start running a turbo or making tons of extra power. Watched a video from Atlas Industries and even they said that if it's properly maintained and not modified, the stock...
That's pretty classic for a stepper motor failure. When some of mine failed, they'd twitch up a little bit when they were supposed to do the sweep, then just fall back, usually below the zero...
Threw an insulated terminal on there and crimped the crap out of it. It's at least three times as thick as what GM put on there, no way this thing ever breaks. Fingers crossed that the connection...
So to finalize, I ended up getting a new old stock Valeo wiper motor from good ole eBay. Part number 15094704. I ended up just swapping on the pulse board from the new motor onto the existing...