Re: 1989 Audi 90 Q rough Idle

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

At 03:39 PM 9/10/98 -0400, you wrote:
>Hello Audi fans.
>
>I  have an idle problem with my 1989 Audi 90 Q.  It idles at about 850 to
900 revs.
>OK, but it feels like it is missing every now and then.  The problem is
not bad
>enough to stall the engine, but it is not as smooth as it used to be
before the
>problem appeared out of nowhere, (or so it seems).  I have already
replaced the 
>idle stabilizer valve, so I know that my problem is not the idling speed,
but rather
>the roughness of the idle.  I have used a couple of bottles of ChevronTehron,
>thinking it may be dirty injectors.  It helped a wee bit, but not much.  I
have
>replaced the air filter, plugs and distributor cap and rotor button, but
not the spark
>plug leads.  Could the spark plug leads be the problem??   The engine
accelerates
>well, stationary and under load.  I am baffled.  
>
>
>I know this is long winded guys, but no suggestions is turned down.  
>Thanks a lot.

Prime suspects:
- Spark plug leads
- Sticky air flap
- Vacuum leak in hoses to ISV
- Ground strap connection on intake manifold
- Drippy (old/partially clogged) fuel injectors

Hope this helps...........SLM

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