Hi,
The most common causes are either an engine vacuum leak or the idle air control valve (IAC) is faulty or needs to be serviced.
The IAC is what is responsible for maintaining the idle speed. It is located on the throttle body.
Here is what I suggest: First, confirm there are no engine vacuum leaks. Here is a link that explains how to test and locate one:
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
If none are found, then I recommend servicing the IAC. Because of the mileage, there is a good chance this is the issue. If the airway provided for the IAC to function is plugged with carbon, the engine cannot idle with your foot off the pedal.
Here is a link that explains how to do this:
https://www.2carpros.com/articles/idle-air-control-valve-service
I attached a picture below showing the location of the IAC on the throttle body.
Let me know what you find or if I can help in any way.
Take care,
Joe
See pic below.
Image (Click to make bigger)
SPONSORED LINKS
Monday, April 4th, 2022 AT 8:06 PM