Hi I have a 96 legacy 2.2L 5spd that had an idle issue. What would happen is when it was warming up it would low idle ( like 300-400rpm) and the car would shake, but when accelerating it was fine. At first I thought fuel pressure regulator was sticky or something, but fuel pressure was fine all the time. I removed the Idle Air control module on the side of the throttle body and sprayed it really good with cleaner. I also sprayed a little in the throttle body itself. Now the car idles like it's supposed to !
So for anyone with an inconsistant idle ( like always too high or low) I suggest cleaning the IAC before doing too much else ( since it only takes 15 minutes).