PIGDOG,
The AAC (located under the throttle body) has a bimetal strip that controls a slide, the bimetal strip is heated slowly on startup, as it is heated the slide moves to close off bypass air, this occurs within approx 60sec of startup. There is no further feeback with the ECU with this item, essentially this is a dumb idle up on start item.

The Idle control valve (IAC i think it is called), the thing attached to the inside of the plenum is constantly controlled by the ECU via Pulse Width Modulation (PWM), this will change the open time of the valve to meet a set RPM target, the longer the valve is open the more air bypasses the throttle body = greater idle speed, this is the closed loop idle control.

If you have disconnected this item then you have no closed loop idle control. You can change the throttle stop screw to stop the butterfly from closing completely, thereby increasing your idle speed, but this is just masking your idle problem.

Bugsie,
As waz1200 has said, if you are running a air flow meter and have an air leak between it an the intake your ECU could calc injector pulse time for the amout of air. A faulty coolent sensor (there are two on the CA, one for the ECU and the other for the dashboard, they are located just behind the thermostat housing) could also trick the ECU into thinking the engine is colder/hotter then it actually is and this will also change the injector pulse time.

Thats my two cents worth anyway.

Bryan