High RPMs before and after IAC has been replaced.

Discussion in 'KJ General Discussion' started by Jamal Jones, Nov 12, 2019.

  1. Jamal Jones

    Jamal Jones New Member

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    I have a 2002 Jeep Liberty 3.7L with a high idle, I have replaced the IAC. 2 to be exact, got a cheap one from Rock Auto didn't fix the issue. Decided to try a IAC unit from Autozone thinking of better quality. Still have an high idle. At idle the rpms are around 1500 to 1700. I have tried to leave the battery terminals unconnected for two days and when reconnected the check engine light will turn on as soon as I start the Jeep. Before If I leave the battery disconnected for that time frame, the computer would reset and the check engine light would not turn on as soon as I started the Jeep. During driving the Jeep on the interstate on level ground the Jeep can almost maintain 60mph without my foot on the accelerator pedal. The computer has been scanned twice, once at Advance autoparts and a local Jeep dealership with the code showing IAC. One of the odd symptoms is when I'm driving on the interstate if I accelerate rapidly bringing the rpms pass 4000 to 4200 and let off the throttle the Jeep will go back to idle rpms for 5 to 7 seconds then return back to 1500 to 1700 rpms. What am I missing?
     
  2. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Try spraying with carb cleaner the IAC port good.
    It should look carbon free /spotless like this !
    [​IMG]
    I used A BWD, but Mopar is best.
    [​IMG]
    Clean the butterfly inside the throttle body and ensure it moves freely, not sticking, and open/closes properly as well.
     
  3. Jamal Jones

    Jamal Jones New Member

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    Cleaning the housing and the butterfly was the first step I took before buying the replacement parts. I have read the Jeep can be temperamental with non-mopar parts.
     
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  4. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    True. The Mopar IAC would be my next step.