Did you check the Idle Oil Fume Valve Gary? You will get those symptoms if it's sticking wide open because so much air gets drawn backwards across the high RPM pipe that the inlet manifold vacuum collapses. The fact that you had no oil residue at all in the throttle body would imply that that they are not swapping over as they should when the inlet manifold vacuum decreases with revs.
To check if it is sticking disconnect the high RPM breather pipe at the join and block the hole near the MAF temporarily, if the idle RPM drops there's your problem. Don't leave it like that though as the engine relies on the high RPM fumes being sucked out the engine there to relieve crankcase pressure and you'll risk weaping gaskets.
Last edited by bren750; 21-09-08 at 10:08.