91 LB9 G92 5spd. Just rebuilt block and heads. Smog, EGR elimintated and prom reflashed to compensate. Sometimes when I push in the clutch to come to a stop it falls on it's face. I've replaced everything in this car. New IAC, TPS, O2, CTS, cam, lifters, timing chain, dizzy and module etc... I even tried swapping back to the old IAC and TPS sensors and get the same intermittent result. Timing set to spec, TPS volts are spot on and no dummy lights other than a faulty vehicle speed sensor. I wouldnt guess a bad VSS to cause a stall condition though. Not sure what else to look at. Any ideas?

 

Vss helps decide engine load. If it doesn't work correctly the fueling/timing will be off at any given time. Fix that first and then come back.