Idle Hunting - '87 5kcstqw

[Swann, Benjamin R. (BSWANN)]

Sounds like a similar problem as what mine is doing.  Car will buck when it
gets in the idle range..kindof like you are giving it the gas then letting
off abruptly, over and over..Annoying to say the least.

BTW - no codes when I checked.

[[From: George Harris <harchris at smokesignal.net>
Subject: 5000CD TQ - Surging in 2nd

Car is running well. Pulls strong in any gear. Smooth. Until I gear down
into second and try to decelerate just using the engine compression. The
car surges and bucks. Most prevalent in 2nd. If I just give a bit of gas
it smoothes right out, but I want to slow down smoothly in traffic. Does
anyone know where to start?

Cheers
George]

> I'm sorting out issues with the new to me 5000 Turbo Quattro Avant.  This
> problem cropped up while I was driving it back from Georgia to MD.  The
> car began surging while I was driving it and slowed to speeds under 50
> MPH.
> 
> I am trying to isolate culprit - engine is hunting for idle, revving to
> about 1500RPM then dropping down to around 700 repeating about 1/sec.
> 
> I checked the throttle screw ( this had caused similar problem before with
> my other '87 5kcstqw), the o-ring looked good.
> 
> I haven't found vacuem leaks - yet.
> 
> I disconnected the ISV connector - no change.  I forgot what is supposed
> to happen.  I may resort to cleaning it, but dont think this is the
> problem.
> 
> I'll be checking the throttle switch next.
> 
> Looking for other ideas and clues.
> 
> TIA
> 
> Ben]