B7 A4 2.0T, p0172 and really rough idle on cold start

Discussion in 'Everything Technical' started by one.8tee, Nov 20, 2018.

  1. one.8tee

    one.8tee Well-Known Member

    Title says most of it. I threw a p0172 code for running rich, and the car has a very rough idle starting it when cold (stalled out if not given gas). After 30 seconds or so it seems to run fine, with a hiccup here or there.

    That hiccup is probably related to my n205 valve being dead, which has thrown p000a and p0011 codes, and that part is on the way.

    Is this pointing to the MAF? I seem to get good readings with it using the torque lite app, around 3g/s at idle, and it scales appropriately with rpms / speed while driving.

    Not sure where to start really. And it seems like the audizine forum for this gen has died out.

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  2. Jeller

    Jeller Posting- God

  3. one.8tee

    one.8tee Well-Known Member

    Would that throw other codes? And why would it seem much worse on a cold start than just all the time? Not arguing just trying to hash out everything hahah

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  4. Deathproof

    Deathproof Well-Known Member

    That could be a bunch of things. I'd startby cleaning the MAF, change PCV, change fuel filter, and check for vacuum leaks. Those are all pretty easy and basically maintenance. Also might want to check fuel rail and FPR, make sure they are clean, also make sure none of the injectors are leaking.
     

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