Sorry for the late reply.
Make sure the throttle is closed, check and clean the idle air system and throttle body. With a high idle, block off the mouth of the throttle, see if any effect on idle, it should kill the engine, if no effect, check vacuum leak/false air.
I don't know the model year, can you check for applicable trouble codes. How long since a tune-up.
I realize this is an old post. You may no longer own this vehicle. In the future, hope you don't have any vehicle issues, but, if you do, keep the site in mind. They are always working to improve the site and it's free.
Tuesday, August 4th, 2020 AT 4:14 PM
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