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S4 running rough, won't rev by 5000rpm.

Discussion in 'A4/S4 forum(B5 Chassis)' started by cossie, Mar 29, 2014.

  1. cossie
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    cossie Member

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    Evening chaps, so got a bit of an issue with my S4. It passed its MOT with no advisories :) about 3 weeks ago so got a mini service done at same time too, fast forward a week and I'm joining the motorway, put the foot down and something didn't feel right. It wouldn't boost as hard as it normally does and felt like it was misfiring slightly. Que squeaky bum time and bad thoughts of ££££! I parked it at home and never drove it till it went to my mechanic last week. What I noticed then was when the engine was turned on the revs idled too high and were erratic. Also when changing gear the revs would stick for a second or 2 before dropping back down. Great I thought, I'll just clean the MAF but it made no difference. Left it with my mechanic hopping for the best. Mechanic can't find any faults, no codes and says ignition coils are fine?? Drove home and it felt a bit better but still not 100%. Now it's back to poor idle, feels down on power and won't rev above 5000rpm, it feels like its hitting a rev limiter. Also the clutch is starting to whine a little when you touch the pedal, I take that's on it's way out too?? I've bought a new MAF in the off chance that'll solve it but won't be here till Tues/Wed. Any advice appreciated, sorry for the novel!
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  2. warren_S5
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    warren_S5 Moderator Staff Member Moderator

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    When were the spark plugs last changed?
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  3. cossie
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    cossie Member

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    Im not sure but would have thought they were done when it was serviced, I'd need to ask my mechanic. If it was a spark plug should he have noticed it?
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  4. warren_S5
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    warren_S5 Moderator Staff Member Moderator

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    You'd expect so, but I had an Audi dealer physically check mine, say they were ok and my car still misfired above 5,200rpm.

    I went and bought some new plugs (against their recommendation as they swore plugs lasted 60000 miles), fitted them and guess what. Problem solved. I noticed some pitting in the electrode tip of one of the plugs, so assume it was less than perfect and caused the issue.
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  5. cossie
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    cossie Member

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    So what about the MAF? Am I barking up the wrong tree?
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  6. cossie
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    cossie Member

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    Sorted! Well, almost. I unplugged the MAF and took it for a drive and its running perfect, even the whine from the clutch is almost completely gone :) Also the car seems super rapid now so perhaps the MAF was playing up before it broke completely and I never even realised. Anyway new MAF should be here in a day or 2 so fingers crossed that should be me sorted. Now it's running perfect makes me not want to sell it but buying a brand new van so think I'm selling the S4 and trading in my old van :(
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  7. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    Whilst is idling and the revs are all over the place disconnect the maf if it returns to smooth idle then the maf is goosed i had same problem on my TQS was as if someone was gently feeding the throttle on and off !!
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  8. jcb
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    jcb Active Member

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    mine just did the exact same thing
    found out the hard way as I pulled alongside a truck on a B road!

    fecking MAFs are ****!
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