won't idle for long

[brother rat]

'94, 2.3, auto, 177k, hasn't thrown the CEL
But if I fire up the truck and just let it idle, after about 30 sec. it starts to lope a little bit (almost like a miss, but it's hard to tell, it's pretty subtle) it will idle like that for 2-3 minutes and then start to die, or in some cases it does die. Exhaust smells a little rich, but again it's pretty subtle (and I'm not a mechanic).
Everyday driving is not really a problem, it's not at a red light or stop sign idling long enough for it to die.
IAC was changed several years ago. Similar behavior, but it would die only with A/C on.
Just looking for some insight, if you have any. Thanks!

 

[Pontiacman]

I'll be interested in answers to this thread. I too have a 94 2.3 doing the same thing. I cleaned the IAC and nothing changed.

 

[GentleRF]

Have you checked the ECT sensor? Or the O2 sensor? Those two tell the ECM what it needs to set the fuel richness or leanness.

 

[RonD]

If you have an EGR(exhaust gas recirculation) system it could be the EGR valve is not closing all the way.
This wouldn't cause a CEL but would cause idle issues.