I bet everyone is fed up of hearing whiney 16v owners and their idle issues

Last week my car started intermittently idling high, or refusing to idle at all. For example I went to start her one morning, and it wouldn't stop at an idle position at all, it ran fine as long as I kept my foot on the accelerator though. About an hour later I tried it again and the car worked perfectly! However after it happened as I tried to go home from work the other day I thought I'd have a look and see what the problem is.
I searched the forum and read a few threads, and I've checked everything (that appears to be!) a vacuum hose and can't find any leaks. I then had a fiddle using this guide
http://www.golfgtiforum.co.uk/index.php?topic=22031.0 and I've got the car to idle perfectly, however now whenever I start or rev the car it falls steadily as normal, then "hangs" at about 1600rpm before very slowly making its way back down to 1000rpm. I've had a look at the throttle body and its clean as a whistle in there (gave it a quick clean with some carb cleaner anyway). The ISV is buzzing away fine and I've given that a good clean too.
I have a feeling that this question has probably been answered before, I just can't find any thread referring to this specific problem!
Thanks in advance and sorry for wasting everyones time again

PS. A mate at work reckons its something to do with the breather pipe, but I can't find any leaks in that either!