audi 100 spluttering when hot

Hi,
Have a '92 audi 100 2.0E (AAD engine) which has been losing power over the last few months. When cold, runs fine, but when hot, at idle, the revs creep
up to about 1200 RPM - if the accelerator is pressed at all, the engine splutters and tries to stall. I've also noticed that the plugs and the exhaust are very sooty. I'm waiting on an oxygen sensor arriving to try that but I have been told that a small sensor/valve on a rubber mount close to the metering head gives trouble. The valve has Pierburg 048 133 517 written on it - don't have a clue what it is.
Anyone with any advice would be greatly appreciated.
Cheers,
Paul
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I would look for a vacuum leak first.
Pull the codes.
paul mcmillen wrote:

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I had the same issue with my TT when I first bought it. Turned out it was the air flow meter. Just a word of caution, if it is buy a NEW one not a used meter. It's not worth it...
Tony wrote:

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