1990 Audi 200 QT Stalling Issues

[gzusoffc]

I have a 1990 Audi 200 Quattro Turbo that I just recently picked up. It is sitting at about 200k but runs strong and is in good shape. The problem it is having is that when it warms up it stalls after revving. It will sit and idle (somewhat roughly) forever but as soon as you rev it a bit, it will drop back down and die and then will not start for 5-10 mintues after. I plugged it in and pulled two knock sensor codes and a code for the coolant temperature sensor. I know the faulty water sensor could cause it to run rich if the computer thinks it is constantly cool but Im not sure what the faulty knock sensors would cause. My question is: Do you think replacing the sensors will fix the problems or are there other things that should be assessed? Has anyone had a similar problem they might be willing to share? Any information would be greatly appreciated. Thanks!
:beerchug:

[scotty33]

Hi

Idon't claim to know much about the 200, but in general, the knock sensors limit ignition advance, if they are faulty you would go into a limp mode where the ignition advance would be limited by the ECU, this could also affect boost on a turbo car. So if the car seems slow at higher revs this would be down to the knock sensors. If it drives well, it could just be an old code?
Try pulling a battery wire for 20mins to clear the codes, see if any new ones come up?
As you say, the temp sender could make it rich. This could affect the O2 sensor which could make it run even richer, try testing the O2 sensor, it may not show a code for a dirty O2 sensor.
Is it a 10 or 20v? MC/3B engine

[gzusoffc]

Thanks for the info...I've had someone else suggest the O2 sensor so I will take a look at that, I have also heard that a clogged cat may be related. The engine is a 10v MC.