Re: 1989 Audi 90 Q Idle hunting

[Steve Manning <stephenm@ix.netcom.com>]

At 07:34 AM 5/27/98 -0400, you wrote:
>Good morning Audi fans.
>
>I have a slight problem with my 1989 Audi 90 Q.  When I come to a stop
light, the
>idle speed returns to where it should be (around 850 rpm), but a couple of
seconds
>after that, it starts to climb up to a 1000 rpm or higher (as high as
11--1200 rpm). 
>Sometime it comes back down to a 1000 rpm and sometime it stays at the higher
>revs.  I believe auto technicians call this "idle hunting".  Does anyone
have any
>suggestions.   Is there a idle stabilizer on this model??  
>
>I am open to any suggestion(s).   Thanks a lot.
>
>Tony .    1983 Audi Q Turbo
>               1986  4000 CS Q
>               1989 Audi 90 Q

Yes, there is a (Bosch) idle stabilizer (I have part # if you need it).

Could be a couple of things:
1. ISV still needs cleaning, or it may be going terminal electrically
2. Full throttle/idle switch acting up (pull the codes and see if you get
anything)
3. O2 sensor on its last legs
4. Vacuum leak (most usually in the two rubber hoses that attach to the
ISV; I have part #'s if you need them).  The white plastick 'elbow' that
one of them attaches to near the firewall gets very brittle w/age and can
crack; I'd just plan on replacing it.

My 02........SLM

Steve Manning:  stephenm@ix.netcom.com
...Physical home: Metro D.C. area, USA
.....Virtual home:  http://www.stationwagon.com