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Thread: Idling low

  1. #1

    Default Idling low

    2003 Silverado 4.8

    When cold it is idling at about 800-900rpm as it should.

    Once it warms up it drops down to 400-500rpm anytime you are stopped.

    If in gear it want's to die.

    The check engine light is not on.

    Any idea's what is causing this ????????????


  2. #2


    How many miles on her? Have you tried all of the simple stuff like check the fuel filter, air filter, etc? You may have some carbon build-up, I'd try something like a good fuel system cleaner too. That's all step-1 and lets you start to rule stuff out.

    After that, I would take a look at the throttle body and check for gunk and clean it out. You can do that whole job in an hour for $15 or less.

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  3. #3


    Has about 65K on it.

    I changed the air filter about 2 weeks ago but haven't checked the other stuff you have listed.

  4. #4


    Cleaning the throttle body did the trick.

  5. #5


    My truck was doing the same thing. For me it turned out I just needed to clean and tighten the battery cables. Might try that.

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