On these vehicles, they used an automatic idle speed (AIS) motor which was controlled by the ECM to maintain idle speed. The AIS is mounted on the throttle body.
The first thing I suggest is to check the wiring to it to make sure there is nothing loose or causing a poor connection.
If that appears good, remove the AIS and inspect the pintel and the area in the throttle body where the pintel inserts. Make sure there isn't a build-up of carbon or dirt. If there is, clean it. If the area is clean, I would recommend replacing the AIS.
The last two pics are the directions for replacing the AIS,
Let me know if this helps or if you have other questions. One last thought, check and make sure the throttle plate is clean.
Take care and let me know what you find.
See pics below.
Images (Click to make bigger)
Sunday, January 1st, 2023 AT 11:57 PM