90 buick regal PLEASE HELP!!!

Hi i have a 1990 buick regal limited 3.1 L engine 170,000 miles.I havent had the car long but th idle is really high until it warms up and then it goes down but sometimes it idles wat too high any ideas?? i just want to sell it

there is a part on the throttle body called an IAC (Idle Air Control) motor. It is an electronic stepper that varies the amount of air allowed in the engine at cold start, closed and part throttle. It functions similarly to a choke on a carburetor, but it's electronic. As the car ages, these can get carboned up and stick, throwing off the air-fuel mixture, and is most noticeable at cold start. You can try removing it and cleaning both the IAC valve itself and the bore in the throttle body it rides in. Be careful when cleaning it that you don't push the pintle in or out, as this can mess up it's calibration.

Here is a link to AC-Delco's website picture of this part.
http://198.208.187.182/internet/ViewPartImage.jsp?acdelcoPartNumber=17112350

What you will be looking for on the car is the black plastic top part (to the right in the picture). The cone shaped piece held by the wire bail in the picture is the piece that goes down in the throttle body and gets carboned up. It is held in place by two screws.

As I have cleaned many of these and I have pushed down on them, they work just fine after I put them back in. They are not calibrated, they are just a solenoid that moves where the computer tells it to based on the other reading it receives from its sensors.