I recently acquired my 1988 GL wagon about a month ago. Everything is sound for the most part and I enjoy the hell out of it. This past week I made a trip out to Tennessee and everything ran fine. On my way back through St Louis I ran into heavy stop and go traffic. When I shifted into first at a stand still noticed that the rpm became sporadic jumping from 1.5 to 2.5 and eventually stalling a couple of times. It never happened if when I tried to replicate it in second or third. I'm going back out that way in about a month and would love to figure this out. Any help would be appreciated.

 

It is an ea82 spfi if that helps.

Any ce codes?

Nope. No codes, no check engine etc.

Could be the trottle potion sensor.. I have noticed I can make mine do the same thing if I don't wait for total warm up... but in your situation is quite different... it could be somthing thing to do with the choke which I am pretty sure has something to do with water temp but I have also read throttle position sensors with have the same Rev up and down symptoms and there is a hose that connects to it and the other into the front of port.. could be cracked ...not unusual that vacuum lines present problems

Edited January 7, 201610 yr by Len Dawg

88 should be spfi, no choke. Unless there is a variation I don't know about...

 

The coolant temp sensor can cause weird random idle variations intermittently. Without causing the ECU to show a code.

Sounds like it's got an auto. I'd start there, those cause problems when they fail

I have had occasions where morning starts rough idled and stalled. I cleaned the IAC by removing the hose and a cap full of Berryman's. Haven't had the issue since.