I have cleaned it up in IPA, put it in a soak bath (thing we have at work) and then blasted all of the crap off it with a compressed air tool! The things cleaner than the day it was made LOL. Also I gave it a jab with a screwdriver (gently) and I could see that the spring/valve was moving easily (possibly a bit too easily for my liking, but then its only Atm. pressure air its re-direcing, not boost!).
I'm not 100% sure if I've fitted it back on properly... The guy I bought it from said it was running like crap when it was cold so he d/c the ISV and all that did was make it run at 1500rpm when warm. Then I showed my mates (who have various 5cyl audis) what I'd bought and they were looking around the engine bay and one of them re-connected something and I didn't really notice.
When I took the ISV off the car to clean it, I put it back in the same way (two pipes connected to it and an electrical connector in the back). And it hasn't changed from what it has been like the whole time... which is 1100rpm tickover when cold and then this rises to 1600rpm after I've been driving it for a few minutes.
To me (as an auto engineering student) it appears that it is jammed open and is feeding the car with more air constantly. The reason it idles lower when cold is because the oil is cold and so the engine does not physically need that much air. And then when it warms up, the oil is warmer and the engine is running more freely and the extra air (albeit atm. pressure) is making the thing run faster on idle. Which is why I think it might be jammed open the whole time.
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