Welcome to AF.
The idle is controlled by the idle air controller (IAC). Sounds like it is putting out high IAC counts. You can remove it and clean all the carbon accumulated over the years off the pintle and dish. Also, a good idea to clean the throttle body out with TB spray cleaner and the air orifice at the seat where it mounts.
We have a pic at our Tips & Maintenance sub forum for location. Held on by two Torx T20 screws.
BTW - On the MAF sensor use MAF or electrical contact cleaner only. Do not get any TB or carb spray on it.
