'87 5KTQ stalling during deacceleration

[Efraim Gavrilovich]

Recently I went through the very same problem with my 5KTQ. It was pretty
scary when it happened first time, the engine just died without any warning
in moderate morning traffic. Anyway, although it might be the deceleration
valve problem, in my case it was a small vacuum leak through one of the
rubber hoses. I suggest you eliminate  the vacuum leak before you proceed to
replace parts.
HTH,
Efraim Gavrilovich
1988 5KTQ 340,000km (211K mi), 1.8 Bar
1990 90 115,000km (71K mi)
Vancouver, Canada

----- Original Message -----
From: "mark" <mconnor at frontiernet.net>
To: "Quattro List" <quattro at audifans.com>
Sent: Saturday, March 02, 2002 3:23 PM
Subject: '87 5KTQ stalling during deacceleration


> Hello Listers.
>
> I have developed a nasty stalling situation recently on my '87 5KTQ.  It
> only happens during deacceleration from highway speeds to a full stop.
> I down shift while approaching the intersection with no problems.  The
> problem usually happens when I shift from 2nd to 1st gear and am rolling
> up to the intersection to Stop.  I noticed the tach in the car as this
> occurs and the needle rapidly dips from around 1200 RPM to around 600
> RPM.  When this happens the engine is on the verge of stalling.  From
> watching the tach it would appear the car is overshooting the idle
> setting and then struggles to right itself back up to 800-1000RPM.
> Sometimes when this happens the car will stall.
>
> I have searched the archives and came up with three possible places to
> start looking.  They are: a bad overrun cut-out valve, turbo bypass
> valve, and/or the idle stabilizer valve.  Based on the list's experience
> what would be the concensus opinion where to start to look?
>
> Since this problem would appear to be related to the idle I am thinking
> it probably is the idler stablizer valve. Is my logic flawed?   Any
> information regarding a potential solution to this problem would be
> greatly appreciated!  Thanks. Mark
>
>
>
>
>