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1995 Chevrolet Lumina Question: Chevy Lumina-Sedan 3.1L, RPM NEEDLE OSCILLATING SLIGHTLY UP AND DOWN, at Idling.

 

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carzen, 3.1L V6, Moorpark, CA, August 01, 2013, 13:51
 Rookie

I recently notice that when my GM Chevy Lumina-Sedan LS 3.1L is idling, its RPM guage needle oscillates up and down slightly and not too fast like vibrating. Also, there is a humming noise from the engine compartment.

I want to fix this problem before it gets worse. Your advice will be appreciated.

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  • Answer #1

    ChevyASE August 03, 2013, 02:56
     Journeyman

    Does the humming come and go as well and at the same time as the Idle changes? How much RPM variation is there?

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    carzen, August 05, 2013, 13:26
     Rookie

    Thanks for your reply! Yes the humming noise come and go as well, it was around the alternator.
    RPM was about 900-800, which is about as usual. I do not believe that my engine has vacuum leak, since I just replaced the lower/upper manifold gaskets and RTV sealed them properly, without any more oil/coolant leaks!!

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