Crankshaft Position Sensor! Was lost in the mail, for several days finally delivered yesterday, been driving today but I'm not ready to roam wherever yet. Short trips it starts/ run without stalling. I might have a subject for a different post. The teeth on harmonic balancer were dirty, a dry rag wiped off dust type dirt but a little brake cleaner on a rag turned 3 teeth white(hey my teeth could use, forget it , totally different post) and the idle not quite as smooth as it was. related? idk! Anyone know what'* on or in those teeth? Back to topic, old sensor had some crud on it some fresh probably from removal but some sort of hardened, been there awhile. Clean and reinstall didnt matter. Thanks for the help and ideas with this. Now I know my battery is weak under load and needs replaced too. Sensor from labwork-parts eBay $9.16(shipped within 24 hrs, USPS lost it after leaving industry,ca). This made a difference- puller from OEMTools kit# 27187+*&h $24.50 includes same general bolts and hardware and others same $$ but also includes 3 bolts and adaptor specifically for GM 3800(I have series 2, should be good for 1and 3 also)and GM 3.1L. Crankshaft bolt 1". Kit 24187 used ¾ & 14mm, but did not include washers. Motor bump with 1" on ½drive ratchet broke CS bolt loose, I never took tire off or had car off ground. Moved(not removed,) overflow tank. removed bat during install with a good screwdriver in one pulley hole locking motor. This is what worked for me. I think new plug wires will smooth idle. But on this subject, we have fire with fire now is time to turn the page🎸 thank you all, and have a good night 🚗💨... 🚓💥
Thus the curtains close on my first live forum topic start. I'd say an easy 5💣 rating! Would be lower but y'all offered good support. And Thanx to GM Forums! Thank You 🐾🐾

I quoted numbers wrong about OEMTools Puller
This is accurate info:
OEM Tools for Professionals
Harmonic balancer puller kit # 27187*
Specialty bolts for GM 3300* and GM 3800
Contact OEM Tools for further info
*My bad.
A Thanx to someone who said crankshaft/camshaft position sensors will only throw a code with motor running. Holds true here.