Discussion in 'General Chevy & GM Tech Questions' started by jdog468, Feb 16, 2009.

  1. jdog468

    jdog468 New Member

    I recently purchased a 2004 5.3 liter Suburban. It runs and drives perfect, but at idle it has what seems to be, a harmonic vibration. It vibrates in neutral or in gear, with the a/c unit on or off, it is not a bad vibration but it is annoying to me, most people probably wouldnt notice it. The vehicle has 60000 miles on it. The dealer acted as though nothing was wrong with it. You can increase the RPM by only the slightest amount and the vibration stops immediatly. The check engine light has not come on. I was wondering if anyone else has experienced this problem, or could tell me what may be causing it. I have already tried putting fuel injector cleaner inthe tank and cleaning the throttle body but this did not help. Any suggestions or comments would be greatly appreciated. Thanks.
    Last edited: Feb 16, 2009
  2. ct9a

    ct9a Epic Member 5+ Years 1000 Posts

    Out of true harmonic balancer?
  3. jdog468

    jdog468 New Member

    Ive visually inspected all of the pulleys and belt, every thing looks normal but my vision is not as good as it used to be.
  4. black jack

    black jack Rockstar 100 Posts

    i wondering if you take white paint and put a dot or line on the balancer then take a timing light and use that to see what the balancer does.
  5. Tunnelmotor99

    Tunnelmotor99 Rockstar

    Just by looking at the harmonic balancer while it is spinning, it will appear to be out of round but it really isn't. GM has an info bulletin about that. I would suspect one of your engine mounts is probably broken.
  6. cascott325

    cascott325 Epic Member 5+ Years 1000 Posts

    this may be irrelevant to the situation, but could it be the tensioner pulley or idler arm?
  7. jb9164

    jb9164 New Member

    My truck has been doing the same thing. I believe that my noise is from the air conditioner pump, If I put just a little bit of pressure on the tension arm on the a/c pump it goes away and my tuck is quiet but when I let go it comes right back?
  8. ponybullitt

    ponybullitt New Member

    Check for any lines touching the firewall.

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