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Coils and Plugs Changed-Still Missfiring

Discussion in 'A3/S3 Forum (8L Chassis)' started by LD3, Mar 5, 2011.

  1. LD3
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    LD3 Member

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    [Mar 5, 2011]
    03 BAM

    Had plugs done few weeks ago at APS as well as getting the red hose replaced as I had a boost leak and just had coil packs done at Audi as per the recall. But it misses on idle and judders though the revs do not rise and fall. Also misses when giving it some and feels like it's holding back.

    Was thinking it might be the Throttle Body needs cleaning? I also hear a small whirring sometimes when the cat has been turned off for about 5 minutes.

    Any suggestions much appreciated
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  3. finesse
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    finesse Active Member VCDS Map User

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  4. Nilz
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    Nilz Defo worth the wait :)

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    [Mar 6, 2011]
    You sure you aint got another boost leak anywhere?
    #3
  5. LD3
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    LD3 Member

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    [Mar 6, 2011]
    If it was a boost leak wouldn't I get sporadic idle? Idle judders but the revs do not hunt as such
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  6. LD3
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    LD3 Member

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    [Mar 6, 2011]
    Will check around the coil packs for wire damage-not worth cleaning the throttle body then?

    Need to bite the bullet and get VAG COM
    #5
  7. wibble111
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    wibble111 needs to scratch the itch

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    [Mar 6, 2011]
    The whirring after you switch off sounds like the after run pump and nothing to worry about.
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  8. murran
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    murran Active Member

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    [Mar 6, 2011]
    compression check? injector fault? have you had it code read at all?
    unplug each coil in turn while its idling.... which one makes no difference to the idle? swap that coil to a different cyl... has the misfiring cyl moved with the coil or stayed where it was?
    #7
  9. talentwalsh
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    talentwalsh Member

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    [Mar 6, 2011]
    I have the same issue as you. I cleaned the TB a while back but didnt realign it. Finally got it re-aglined and it seems to have improved it a fair bit but not fully. Maybe worth a go.
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  10. LD3
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    LD3 Member

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    [Mar 6, 2011]
    Had a compression check done when I was at APS after pipe chnage and I don't think it's a boost problem. Will have read at Audi or a VAG COM and see what that throws up
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  11. fran-s3
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    fran-s3 Active Member VCDS Map User

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    [Mar 6, 2011]
    I had a similar issue when I had my car remapped. Driving me mad, changed all 4 coils, plugs etc. Missifired only when giving it the beans. After APS had it for the week to investigate turned out to be my fuel pump! Basically it wasn't pumping enough fuel when it full beans hence the misfire. VAG-COM never threw any codes, worth thinking about but like a lot of these things it's a case of trying it and see. Best thing you can do is log it via VAG-COM on full beans when it missfires block 62 I believe gives miss fire count. Mine was doing it on all 4 which obv meant not all 4 coils had failed again but would suggest them all not getting enough fuel which would suggest the fuel pump. Anyway something to think about - could be something else obviously. Before my remap it was completey fine i.e not missfiring.

    APS told me to look at my exhaust tips, sure enough they were corroded on the ends (and ruined!) thus suggesting it was running lean and had been for a long time. I had no idea - so worth looking at your exhaust as a tell tale sign of running lean - also my engine bay would be incredible hot after a run. Hope it helps.
    Last edited: Mar 6, 2011
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  12. LD3
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    LD3 Member

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    [Mar 7, 2011]
    Fran interesting reading thank you. Mine has been remapped prior to me buying it-something which the seller (who was a performance car trader) said it wasn't. Guess that's why I've changed 3 rubber pipes in as many months-previous owner didn't even do the TIP.
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  13. LD3
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    LD3 Member

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    [Mar 7, 2011]
    Might just do it anyway-lord knows if it has been done before
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