91 Accord idling problem
 

Having an idling problem at stop in Drive....wants to choke and die.
Have original 400.000 miles No check engine light, have kept car well maintained.
Idles OK in Park Plugs wires vacuum lines all good....any suggestions ?????

Check and clean the ground connections: transmission, engine (valve cover), thermostat (main ground for ECU), car body, and negative battery terminal

Maybe the engine coolant temp sensor or MAP sensor.

Describe the idle
-when engine is cold
-when engine is getting close to operating temp
-when engine is at operating temp

try cleaning iac sensor

I'm with ChrisS, Coolant temp sensor. If I remember correctly, it is screwed into the thermostat housing. it's a pretty cheap part. It it fails, it sends the wrong temp reading to the ECU and the the car adjust the timing to compensate for an incorrect temp. I've swapped mine twice.