2001 Mercury Cougar idling high, IAC replaced

Asked by Feb 19, 2017 at 09:59 PM

Question type: Maintenance & Repair

My son's 2001 Cougar is idling at around 3000
rpms when stopped, it will jump between high idle
and almost dying. When he puts it into park it will
die. When he comes to a stop (for instance, at a
stop sign) the car will lurch forward like it's trying
to go. He replaced the IAC valve and sensor. A
mechanic looked at it last week and said that when
he unplugs the sensor, it runs great, but will die
when you stop. He checked the car over and found
no vacuum leaks. He said it's like there is a
malfunction between the IAC and the computer,
but no codes come up. Does anyone have any idea
what this could be?

2 Answers


There's also a sensor related to the IAC circuit- about $50 part. You also need to reset the computer when replacing the IAC motor so it will re-learn. I hope you cleaned it when it was apart.

My blows but only out of the defrost I know it's a vacuum but I can't find or locate where that vacuum is to replace it and then I need to know if it what the duel vacuum port on the carburetor is that the vacuum for the air conditioner

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