Low power in my AUDI 200 AVANT Quattro Turbo 20V

[SuffolkD at aol.com]

I like this guy already!

My guess is the ISV Idle Stablization Valve.  Photo here:
http://www.quattro123.com/ISV.htm, 
however I think I have a similar "sometimes" problem too.

The ISV will do the CEL Check Engine Light, then go off like you say.

I think my thermostat in the engine head is open a little all the time.  This 
makes the car run COLD in the Fall Winter and Spring.
If the car idles until HOT, I get 1.6 bar or more
If its COLD I get 1.3 bar, so it sems intermittent when It does one thing 
then another later.
Try those two things.
-SCott by BOSTON

<< From: "Maurizio" <>
 Dear sirs...I will be crazy !
 The car was fantastic......when it work fine...but...... 
 
 Engine 3B
 
 1) When it work fine the max pressure of turbo (read on the digital 
instrument on the cockpit) is 1.7 bar; (in the previous time 1.8 bar).
 
 2) I've change the bypass valve, the waste gate freq. valve, the two knock 
sensor, all the ose from / to turbo and so on, multifunction temperature 
sensor, air filter, MAF sensor, fuel pump and fuel filter, the fuel pressure 
regulator, the number 10 relais....but the operation was very strange!
 To control if the overboost send the correct signal to the waste gate freq. 
valve, I've attached one little lamp in parallel to the connector.
 So, the overboost not every time work....without reason work yes...work not.
 The max pressure was 1,4...1,5....1,6.....rarely 1,7 when the overboost work 
fine.
 The max pressure was...1,2......!?
 The check engine light is on.....without reason..then is off......then is 
on.....then off (when on for 1 second max)
 The only fault code is 4442 ! (In one time 2234)
 Waht can I do?
 Can you help me...?
 Many thanks
 Best regards
 Maurizio - Como - Italy
 
 I think that I'm the only one owner in Italy of this model, so I want my 
beautifull car in perfect conditions....the test on traffic lights give me a big 
smile..... >>