a6 throttle body/idle issues?

hi, i have a similar problem with my a6 1.8t, started to fluctuate between 1-2000 rpm, i tapped the throttle body with a stick and it stopped, took the whole thing off and cleaned it and now its worse than ever, renewed all the breather pipes, now will slowly creep up to 1500rpm, turn off the engine and restart - returns to normal - this doesent always happen though, some days it fine. took out dump valve operated by breather pipe from inlet manifold and put a through joint on the pipes, blanked off where the breather pipe is fed from manifold and it was fine, so i bought a new dump valve, worked fine for 3 days then back to old tricks!
took off throttle body and removed platic cover, totaly cleaned poteniometer with cleaner, etc, when problem arises throtte body valve doesent change status, ie its in the norm position. thats why i was sure it was the cut off valve!
any ideas very wlecome, anything i can tinker with in vagcom???