Audi Repair: Engine running uneven/sluggish., vacuum leaks, efi motor

Question
Hi Jan.

There are no VW experts around here. So, in desperation I turn to you. If you think I'm out of line asking you this question, I understand, and will not give you a low rating if you refrain from answering. Seeing as Audi (I own one if those as well) is a close relative to VW (V.A.G.) I'm giving it a shot with you.

I have a 92 VW Polo, 1,3 litre manual transmission EFI gasoline engine. Current mileage at 63000.

Recently the engine has begun running uneven/sluggish at low rpm, both when standing still, and while driving. The engine never dies. It just keeps running unevenly, and only at low rpm. The engine responds readily when I push down the gas pedal, so it's not sluggish when accelerating. Nor is it sluggish if I just make sure the rpm is above about 2500. Also when accelerating on lower gears I can hear a rapid, on/off "squeaking" sound from the engine. It's not very loud.

There is one exception to this:
-The problem is not so much there just right after start up on cold mornings, and for the first 3-or-so minutes of driving, leading me to think the auto-chocke at start up prevents the problem to some extent.

I've checked the timing belt, and it seems in fine condition. I've also recently replaced the spark plugs and the rotor.

So now I wonder if you perhaps could help me with a few tips on what to look into next. Or maybe you already have a pretty good idea of what may be causing the problem.

Many thanks in advance.

Regards
Vegard Clausen
Norway

Answer
Hi Vegard,

Thanks for your question.  You are right, VW/Audi are close relatives, btu the 1.3 EFI motor is not used in Audi's.  Anyway it does sound like there is a problem with the idle control.  I would first check for vacuum leaks, and also if there is an idle control valve make sure that is working correctly.  Do those checks and let me know what you find...  Jan