St...St...Stuttering Problem

[Eric Renneisen <renneie@hlthsrc.com>]

My CQ's idle problem is back (watch out, Ian, yours can't be far 
behind).  Last time, just unplugging the ISV and reconnecting it 
made the wandering idle go away.  That was months ago.  I figured 
that the problem was corroded electrical contacts in the plug.  
Now, it's doing it again, only worse.  Idle searches between 400 
and 1400 RPM.  Several times I've had it stall on me when I press 
the clutch and the RPMs drop _way_ below normal idle.  If I unplug 
the wires to the ISV, the idle drops, but I think it's still 
fluctuating slightly.

Normal procedure is to clean and soak the ISV in carb cleaner, 
which I will do this weekend, but I was wondering if another 
problem might be related.  This has to do with a stuttering effect 
when lifting the throttle.  I originally thought that it was 
happening when lifting the throttle at any position, but as it's 
gotten worse, it seems to be happening in the last few centimeters 
before my foot is completely off.  The car will suddenly vibrate 
and slow down as if under hard engine braking.  Another new 
development - when shifting gears, the first few centimeters of 
throttle travel seem to _slow_ the car!  It feels as if the fuel 
supply is suddenly cut off.  Everything's fine as long as I keep 
my foot deep into the go pedal.

The ISV couldn't be causing all of this, could it?
Someone suggested a fuel filter problem, and I am going to replace 
it ASAP.  At 108K it's probably about time anyway.  Could it be 
causing this?

As an aside, what's the consensus on fuel filters?  Stick with OEM?
Use anything that fits?  Where to buy?  Should anything else be 
done while I'm down there.

TIA

Eric Renneisen
'90 CQ 20V  -  my 'running-iron'  ;^)
Chattanooga, TN

Apologies to Bob Newhart, that country music singer who's name I 
can't remember, and any other chronic stutterers - I do it myself 
sometimes.