Classic/Antique Car Repair: fast Idle on a 1988 Lincoln Town Car, lincoln town car, warm weather

Question
After putting my car in park it will idle real high after awhile it will idle back down and when I come to a stop at a light it will do the same but not idle back down in the time I sit there. It does not like to start in cold weather in warm weather it will crack right over. It is a 1988 Lincoln Town car what could be the problem or problems I could check. Thanks Steve

Answer
There is an idle control sensor that senses when the car is warm.
Some sensors will idle even higher when the car is warm to let you
know its time to release the automatic choke. This is done by quickly
pressing and releasing the accelerator to release the choke. Some cars
has an automatic choke release. In either case, the car should return
to a slow idle. If not, the sensor is most likely bad.