NRB20V

Just picked up a 1991 200 20VTQ Avant.
Had the speedometer problem, soldered the weak spot, Fixed!
Another problem I am having is that when I go to 4-7 RPMs and push the clutch in, it drops RPMs to around 3-4 hundred and occasionally stalls.
So far it does it in 1st and 2nd gear, haven't have too much trouble at 7000 in 3rd

Anyone else have this problem or know how to diagnose?
Thanks.

Prospeeder

There is the Auxiliary air valve which could be sticking, or not working. There is the throttle position sensor which must work correctly so that when the throttle closes, it commands the aux valve open and prevent it from stalling.

Kneale Brownson

Turbo bypass valve failure: Read all about it on Scott Mockry's helpful website: http://www.sjmautotechnik.com/troubl.../20vbypas.html

NRB20V

I've read it could be the Turbo Bypass but is there any change it could be the idle stabilizer? I will order a bypass and replace that. Any deals?
Part number
W0133-1734032

Prospeeder

well yea, did you just ignore my post lol. Aux air valve and idle stabilizer same thing. If the ecu isnt getting the closed throttle signal its not going to open the idle stabilizer and car will just stall.

NRB20V

I wasn't aware that Aux air valve and idle stabilizer were the same.

I will run the voltage test on Aux air valve and see if there is any problems there as well.
http://www.sjmautotechnik.com/troubl.../20vthrot.html

Thanks for the responses.

NRB20V

Bosch Throttle Switch
Part Number: W0133-1610779

Genuine Turbo Cut Off Valve
Part Number: W0133-1734032

Bosch Idle Control Valve
Part Number: W0133-1601849