[V6-12v] all quiet on the AUDI Front

[Tom Christiansen]

James,

>a) it seems to occur more or less at the same point on pressing down the 
>throttle each time (neither light, nor heavy, but on the transition 
>between the two.

Which is probably the most common throttle position. So the pot wears most 
in that position. - Just like the steering rack wears mostly in the center.

>b) it happens more when cold, or when the car has been idling (so there's 
>no current going through that part of the pot to clean it temporarily, or 
>for the voltage to re-establish a connection.

The cleaning of the pot is purely mechanical. I highly doubt 
voltage/current will do any cleaning for you.

>So yeah, good thinking... is there a way of 'cleaning' those pots though, 
>or do you just replace them at this age?

Based on my experience with ordinary pots in misc. electronics gear, I'd 
suggest replacing the pot. With a thorough cleaning you might be able to 
make it work for another couple of months, but then it's time for another 
cleaning. If the problem is caused by wear and tear on the pot, no cleaning 
will help.
Anyhow... If you want to clean the pot, you'll need access to the innards 
of it. On normal pots there is an opening where you can spray some 
electrical contact cleaner, but I don't know about the throttle pot. Maybe 
you can take it apart and clean it.

Tom