Intermittent engine vibration and noise

Discussion in '96-04 - 2V Specific' started by _ExpeditionMan, Jul 10, 2014.

  1. _ExpeditionMan

    _ExpeditionMan New Member

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    I purchased a 1998 Mustang GT with 159K on the clock about 3 weeks ago. The interior and exterior needed some work, but I thought the powertrain was solid. I JUST transferred the title and registered so it figures I would start having issues now!

    Anyway, I am driving home from work and am accelerating in 2nd gear, I was not flooring it or being rough but I happened to let it rev to ~3500 rpm. At 3000rpm I heard what seemed to be a whirring in the engine compartment, almost like something was loose and shaking. It does not sound like metal on metal. It would start at 3000rpm, cut out between 3100-3400rpm, and come back at 3500rpm then I shifted. It wasn’t loud or grating, but it was audible. The sound reminded me of a time I had a couple leaves stuck in a fan and they were rustling around. I was able to replicate this again in second gear later on in the night. It does not occur with 1st or 3rd.

    Additionally, I get some brief engine vibration between ~1300-1500 rpm. It is smooth when in gear and driving but if I am sitting in neutral and still and rev the engine the vibration will occur in that range on the way up and on the way down. I can feel the vibration in the steering wheel and “in the seat of my pants.†I wouldn’t call it violent. The closest thing I can associate it with is the same feeling when my Acura had a lot of carbon build up in its intake and EGR valve, but that was only at idle, which was a very rough (and occasional stalled). The vibration with the mustang is not as severe. The exhaust does not sound consistent at idle, almost like it is coming out in spurts instead of a constant stream of pressure, you can even feel it if you put your hand up to the exhaust tips.

    I get the feeling that the issues are not related and it is just a coincidence that I noticed them on the same day, though I am not sure if that makes me feel any better… No check engine light is showing. Any help you guys could offer would be greatly appreciated, sorry for the length of the post and hopefully it is in the correct area. Thanks!
     
  2. CC'S95GT

    CC'S95GT Legend

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    probably the harmonic balancer.
    My son's 98gt just had the HB come apart last week. Luckily he was close to home.
    The whole outer ring came off but the belt stayed on what was left. Weird.
     
  3. _ExpeditionMan

    _ExpeditionMan New Member

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    Hmmm I guess that could cause the vibration at certain RPMs. The engine doesn't move around a lot in the bay which eliminated the motor mounts to me. Would a bad harmonic balancer make noise?
     
  4. CC'S95GT

    CC'S95GT Legend

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    The vibration could also be u-joints
     
  5. dirtyred11

    dirtyred11 Active Member

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    I have the same vibration as you are referring to, it started after i replaced my clutch and flywheel in my 2000 GT. It was worst when i first replaced it but it is just as you are describing your symptoms now. Hope this helps...
     
  6. _ExpeditionMan

    _ExpeditionMan New Member

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    Would I be able to diagnose this by crawling under the car and finding play by hand or is there a better way? My harmonic balancer looks fine, no chipping and doesnt look to be spinning off-balance..

    Thanks for the input, anything is appreciated. I noticed more vibration at idle on the commute this morning, could just be sensitivity since I know something is up. How long ago did you replace your clutch and flywheel?
     
  7. CC'S95GT

    CC'S95GT Legend

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    if the u joints are really worn out then you'll be able to feel the play but sometimes not.
    U-joints are cheap and with a press or a large C clamp, both can be changed out in a couple hours.
     
  8. dirtyred11

    dirtyred11 Active Member

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    Thats when i notice most of my vibration also is during idle, and i replaced it back in marck sometime and i have put around 1500 to 2000 miles on it since and still have the vibration.
     
  9. _ExpeditionMan

    _ExpeditionMan New Member

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    Thanks for the help guys. I managed to track down the whirring noise. I pulled the center console while doing some cleaning and was driving around without it when I noticed the sound was coming from my transmission area not my engine. Seemed to happen when under more than 50% throttle, upper rpms, and whenever I take it out of gear. Still that same rattling like something is loose. No news on the vibration though.