[s-cars] ISV Cleaning, was: Translation

[Marc Gorelick]

Kent McLean wrote:

>Toborg Michael (AC/ESC3-CC) * wrote:
>  
>
>>Multi Function Temp Switch
>>Mass Air Flow (Sensor) 
>>Blow Off Valve
>>Idle Stabilization Valve.
>>
>>Carb cleaner? Also curious about cleaning the ISV.
>>    
>>
>
>http://www.audifans.com/twiki/bin/view/Audi/IsvCleaning
>
On a related note, perhaps someone can tell me if this is an ISV 
problem. Patient is a '93. Car idles great except for the problem below:

When decelerating on approach to a red light, I usually just pop the car 
out of gear and hit the brakes. Often when I do this, the engine RPMs 
will coast down to the normal idle speed and then keep going, down to 
the vicinity of 500 RPMs or so. At this point, something realizes that 
the RPMs are too low and the engine speed rebounds well past the normal 
idle, up to as high as 2,000 RPMs.  After this the idle immediately 
returns to normal.

This occurs about 1/3 of the time when I am decelerating as I approach a 
light. So far a bit of experimentation seems to suggest that if I stay 
off the brakes the problem doesn't occur.

Since the idle is rock-steady other times, so I wonder if this is ISV 
related or something else entirely. My assumption is that an ISV problem 
would show itself at other times as well. Anyone seen a similar issue?

Thanks for any feedback,

Marc