My friend's 90 Integra LS is having idle problems...Its bouncing up and down from 1grand to 2grand and when you turn the AC on it drops to 1,000 RPM

He thinks its the Map Sensor and unplugged it to see if the problem changed...I told him that unplugging it will not show him anything but a check engine light and high idle...The fast idle screw is adjusted to the minimum and the problem persists...

Any help will be appreciated...The car doesn't want to stall at all, so I don't think its a vaccuum leak, plus we can't hear a damn thing leaking and we checked the visible vaccuum hoses and they are secure...

Thanks in advance,
Zee
intikab@cs.com