papyrus

I've been going NUTS with a recurring issues for months now. I finally got a VAG after various shops could find nothing. We've replaced coil packs, POS, MAF, plugs... no luck.

AWE Stage III car... a6 actually but you know the drill.
I'm down to two codes I'm seeing right now:
17537 - Fuel Trim; Bank 2 (Mult): System too Rich
P1129 - 35-00 - -
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 35-00 - -

Here are the symptoms: Once I clear the codes it runs great for a day or two. At some point while driving I feel the a/c blow a touch warm for a second (no schtik). After that the majority of boost is gone. it is not completely limp mode, runs relatively smooth but massive drop in boost. Within a few miles the CEL usually comes on - but def. some time after the boost cut. Once it's in this stage it is a bear starting cold. Disgusting spitting misfires and wanting to die until it suddenly pops up to 1200rpm and runs smooth. If I clear the codes it runs and starts beautifully.
I have some crazy idea this is all TBB, because the shop that did the work and troubleshot replaced it with a stock unit when it tore once under the explanation that the 'new' factory TBB was very tough. Would that throw (only) 17537/17535 codes? Also - the shop was seeing many misfire codes earlier, although I haven't seen thems since putting the VAG on it myself.

Any thought of what to try next or additional VAG data that would be helpful? Thanks much in advance.

B5QShip

pressure test recently? Sounds like a big leak to me...

lemieux@curbside

<img src="http://pictureposter.audiworld.com/47312/back_of_2.7t.jpg">

lemieux@curbside

you'd hope that the shop would at least know that much ..1-st pressure test a turbo car ..

papyrus

yeah they said they checked that... hence steering away from tbb... but i dunno, something makes me keep thinking that.. i think its the way the whole saga began with it completely dying under WOT and nosediving.

papyrus

No definitely did not check/change that. Does that sensor feed into any gauges at all or just into the ECU for calculations? if you don't mind me picking your brain, what's the logic flow from a bad reading on these to the too-rich deal? Also - what 'mode' could the car be reverting too that would pull so much boost without completely limping it - or is this the stg III limp? Im also curious why/how it 'limps' before the CEL comes on. Thanks again.

lemieux@curbside

the engine "thinks " it's cold so it gives fuel according to that reading .. it's a known problem.. especially if you have the black sensor (old -problematic one).
that's why awe includes it with their kit.

lemieux@curbside

fuel pressure regulator .. maybe stuck and too much fuel goes in.
check the ECT first !

papyrus

Thanks... I also read about how the engine will kill the a/c in repsonse to a hot reading here. When these things are flaky do they give erratic readings both cold and hot? Also - my temp gauge always look stable - does that refute this whole theory or is that from a different source?

I'll touch base w the shop and see if they changed the sensors... also would this tie into earlier misfires?

Thanks yet again

lemieux@curbside

<ul><li><a href="http://search.audiworld.com/?q=misfires+coolant+sensor&amp;u=&amp;s=all&amp;ca t=010006&amp;db=1999-01-01&amp;de=2006-09-22">http://search.audiworld.com/?q=misfires+coolant+sensor&amp;u=&amp;s=all&amp;ca t=010006&amp;db=1999-01-01&amp;