Some of you know I'm chasing a high idle. When It warms up it will steadily go to 2000rpm in P and N and when I put it in D or R it comes down to a notch under 1000rpm and recently it will settle around 800rpm and when the AC is on it will drop a little more to around 700rpm.

I've changed all the vacuum lines and rubber parts (all of them). The gauge for the vacuum is only completely to the left when I'm crushing on the FW, with normal driving it's a notch towards the right.

Today when the car was started up (cold) and while the car was running I was leaning on the air filter housing and to my delightness the engine stayed at 900/1000rpm, no surge to 2000rpm! Ran it in D and the RPM would stay at 700/800rpm. Turned the engine off and when I restarted it again it would immediately go to around 1800/1900rpm, after pressing the air filter housing firmly again after 20 seconds the idle went down and stayed at 900rpm in P. When the engine is hot it will immediately go to 2000rpm.

When I replaced the rubber boot underneath the MAF I had a hard time getting it fitted on the throttle body and I suspect now that's where the cause is. Or could it be the gasket for the throttle body or anything else?

Anyways, what's the best way to make sure the boot go's firmly on the throttle body, it's sort of guess work when installing it?

__________________
1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).