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No deception here - 1990's do indeed have an IAC. Actually I've never heard of an LH 2.4 that didn't. Anyway...
The IAC is not adjustable. The opening angle is normally controlled by the ECU (Engine Control Unit). In the event of a problem and the ECU is unable to control the ECU (bad wiring, bad IAC motor, etc.), in the unpowered state the IAC should return to a failsafe, partially-open position by an return spring.
The adjustment on the throttle cable is for wide-open throttle adjustment only. There is a small throttle stop screw and locknut on the throttle lever, but that is not an idle speed adjustment and in most cases should rarely be touched. (This isn't your father's Oldsmobile.)
A major component of the idle speed system is the throttle position switch, attached to the throttle shaft. The TPS contains two switches, one to detect closed throttle and the other to detect full throttle for fuel enrichment purposes. Only when the ECU senses closed throttle does it attempt to maintain the engine speed above the preset limit.
You should hear a distinct 'click' from the TPS when the throttle is cracked open. The manual states the switch should be closed with a .15mm feeler gauge between the throttle lever and the throttle stop screw, and should be open with a .45mm gauge.
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