Like others have said..............check the idle and WOT switches.
I will assume that you have the Digifant II system, but I am not sure on
this.
If you do you might find a wiring problem at the intake manifold or cylinder
head (ground wire breaks)
Or maybe a defective Fuel Pressure Regulator.

IF CIS-x, it might be a wiring issue (again ground) at the cold start valve.

Just to give you more things to check.
DON'T JUST THROW PARTS AT IT!!! Check it out with a digital Volt Ohm Meter
and a good book (Bentley). ;-)

--

later,
dave
(One out of many daves)


"dan" > wrote in message
...
> Spar > wrote:
>> I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
>> the third 3rd time it failed.
>> Have installed new oxygen sensor, new catalytic convertor, new plugs and
>> changed the oil. The vehicle does have eratic idling at certain times
>> and
>> not all the time.
>> One mechanic today suggested I change the Idle Stabilizer Valve.
>> Would appreciate hearing from anyone who has experienced eratic idling
>> and
>> have them advise me
>> what repair was necessary to fix it.