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Random revs to 2000rpm

Discussion in 'General Automotive Chat' started by joebrown90, Apr 9, 2013.

  1. joebrown90
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    joebrown90 New Member

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    [Apr 9, 2013]
    Hi,

    i recently cleaned out my Audi A3 (1997) trottle body due to poor idleing (wanting to stall all the time) this worked really well, untill i got it home and it started to rev (by its self) to 2000rpm.

    the car doesnt want to stall anymore but now the idle is up and down like a yo-yo.

    can someone please help me as this is becoming an annoyance!!!

    ive seen that people have put things up about this before, but i'm finding it difficult to make it relevant to my car.
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  3. JudderMan
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    JudderMan Active Member

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    [Apr 9, 2013]
    Unplug the MAF sensor and see if it's that. I had similar recently and couldn't figure out what it was at it only happened after driving fast. I normally drive like a saint so it didn't crop up, people on here was saying it could be a vac leak but one guy said to unplug the MAF and it idles perfectly now. Just need to buy a new one now...
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  4. joebrown90
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    joebrown90 New Member

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    [Apr 9, 2013]
    Thank you for replying, this is the first time i have used this so i was a little unsure if it would work.

    is that the plug directly underneath the butterfly valve itself? because if it is, that seems pretty clear/clean. also, i've seem that some people take it all the way out (by unscrewing it) is that what you mean by unpluging it?
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  5. JudderMan
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    JudderMan Active Member

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    [Apr 9, 2013]
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  6. joebrown90
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    joebrown90 New Member

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    [Apr 9, 2013]
    ok great, my set up is slightly diffrent to that picture. is that a newer model? i guess it will be in the same area on my 1997? what should i use to clean it?
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  7. JudderMan
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    JudderMan Active Member

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    [Apr 9, 2013]
    It should be very similar. It's the connecting pipe (in a T shape) that goes into the air box. It has an electrical connector going to it. Pull that off and if it idles properly then it's the MAF. You can't clean it, just needs a new one. Bosch (OEM) are £120 I think.

    BTW - I just nabbed the photo off Google Images :)
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  8. joebrown90
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    joebrown90 New Member

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    [Apr 9, 2013]
    i now understand, bugga!!! i was hoping you could clean/repair them. i'll have a go after work and hopfully it will work.

    my only question is really about the random reving to 2000rpm, is that it wont just rev that much and come down again it would go to 2000rpm then after driving off again it would come down. its almost something gets stuck. would that still be the MAF?
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  9. JudderMan
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    JudderMan Active Member

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    [Apr 9, 2013]
    I can only really give you what I've experienced as I'm no expert, but mine was only from driving fast then coming to an idle and it would be rough ie 200-400rpms. Then it was like the cold start/fast idle kicked in or anti-stall (if that's even on my car) would launch the revs to 2krpm (as what you're describing) then it would go back to 200rpm. I could rev it and pull away and it would be fine through the gears, not stuttering at all. Then it started doing it all the time even after driving at sedate speeds so I assume the MAF was on its last legs and is now dead.

    If you unplug it and it still does it then it's probably vacuum related, look for split pipes or loose fittings across the whole intake system. Yours could be throttle position sensor if you've taken off the throttle body? Do you have VCDS to do a scan? Mine doesn't say that it's the MAF but the lambda sensor instead, but unplugging the MAF has hopefully pointed at the culprit as I don't want to have to buy a lambda as wel.
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