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s3 idling funny

Discussion in 'A3/S3/Sportback (8P Chassis)' started by c6dsy, Nov 27, 2012.

  1. c6dsy

    c6dsy Member

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    My s3 started idling weird tonight i drove about 8 miles and then was out car talking to someone then jumped in the turn round and noticed revs dropped down really slow then changing gear was getting backfire once home i took it out of gear and let it idle and its fluctuating between 2000 rpm and just below 1000rpm going up and down and if i rev it there is a back fire too any ideas? Got an ig maxogen fitted and full miltek turbo back exhaust
     
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  3. mjr901

    mjr901 Parts Manager - (Main Dealer)
    Audi Main Dealer Gold Supporter Audi S3

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    you could try cleaning the MAF.
     
  4. c6dsy

    c6dsy Member

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    where is it? and clean it with what?
     
  5. MrLapou

    MrLapou Well-Known Member

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    Vacuum leak. Oil filler cap seal leak.
     
  6. c6dsy

    c6dsy Member

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    Cant seem to find any leaks but when I turn it off the circular plastic bit on front of rocker cover hisses away for a bit maybe 15 seconds it has a small hole that is meant to be there that's where air is coming from
     
  7. 170sam

    170sam New Member

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    PVC valve common fault
     
  8. c6dsy

    c6dsy Member

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    just replace that then see how it goes?
     
  9. 170sam

    170sam New Member

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    My bad pcv valve
     
  10. 170sam

    170sam New Member

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    Yea replace it I'm sure it will fix your issue
     
  11. 170sam

    170sam New Member

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    Yea just replace it and I'm sure it will fix your issue for you .
     
  12. MrLapou

    MrLapou Well-Known Member

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    Try taking cover off with engine running to see what happens.
     
  13. c6dsy

    c6dsy Member

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    if i take oil cap off it runs worse then air hisses out valve at front i will try pcv valve
     
  14. jaydav2306

    jaydav2306 Member

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    What is a PCV valve and what does it do????
     
  15. c6dsy

    c6dsy Member

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    Its a valve on the front of rocker cover that takes breathers from block and inlet manifold and has a diaphragm in it to alow them all to breath, seems if diaphragm breaks air leaks straight to inlet causing idle to fluctuate
     
  16. jaydav2306

    jaydav2306 Member

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    Is this the thing located on the top left hand corner above the oil cap? Good to know
     

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