If your engine continues to idle real high after it's warmed up, check the air regulator unit. It's located on the passenger side of the engine, below the intake manifold, near the rear. There's a hose connecting to it. Pinch the hose when you are having the high idle condition. If the idle speed drops, there's a problem with the unit. Also check the electrical ground connections on the engine for looseness and oxidation.
Another thing to check for is an air intake leak somewhere along the intake plenum between the Air Flow Meter and the Throttle Valve. Check all the nuts for tightness that fasten the intake system to the engine.
Adjusting the idle is pretty straight forward:
Disconnect the TPS harness and turn the idle adj. screw on the IAA to get the car to idle at 650 rpm. Reconnect the TPS harness and your beloved should purr at 700 or so rpm. (The Factory manual gives a +/- tolerance of 50 rpm.) The IAA is at the back of the intake manifold. You can see it standing over the right (passenger side for N.A.) fender and looking at the funky device with the dime size recess for the adj. screw.
Contributed by: RogoMan
