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rpm's slow to drop back down to idle

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Nem, Jan 28, 2009.

  1. Nem

    Nem New Member

    i can understand a little bit when its cold but it gets way high when cold and even when truck warms its a little slow to drop back down to idle.

    its a 99 1500......any ideals what it can be?

    thanks for any help
  2. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Might be a vacuum leak or one of the emissions sensors. Poke around under the hood and look for loose or cracked vacuum lines. Could be the EGR valve too. Check for DTC codes if the check engine light is on.
  3. Nem

    Nem New Member

    ill check for leaks but runs nice and smooth when it finally comes down......no engine codes either

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