Ford Repair: 06 Taurus, air control valve, faulty sensor

Question
What would cause the car not idle down for some time after starting it, whether it is a cold start or restart.  You have to set and wait for it to idle down from 1200 to 1400 RPM's down to about 700 RPM's.  We have changed the water
temperature sensor and the sensor on the air intake. Do you have any other suggestions. It is a 3.0L V-6"


Answer
Try cleaning the throttle body,in particular the idle air control valve.You will need to use air intake and throttle body spray with a cotton towel.If this does not help,have a diagnostic run on the car,and not at a parts store.We don't need to know the codes,there probably are not any present if the check engine light is not on.A scanner,such as a genesis,will tell three things.What the sensor reads,what it is suppose to read,and what it actually is.This may reveal a faulty sensor that for one reason or another hasn't tripped the check engine light.