The minimum idle speed is set at the factory and usually does not need any adjustment in the normal operating conditions; nevertheless, should the throttle body be changed or any reason to suspect that there is a problem with the minimum idle speed, it is recommended that the vehicle be taken to a qualified automotive repair shop. The PCM varies engine idle speed by operating the Idle Control Valve, which is installed on the throttle body and regulates the quantity of air entering the engine by passing through the closed throttle valve, according to the load on the engine, like running the air conditioning or the automatic transaxle. Firstly, make sure that the ignition key is turned to the OFF position and take off the air intake duct. To the models between 1994 and 1998, unscrew throttle body, unscrew Idle Control Valve mounting screws, unscrew Idle Control Valve, then replace the old gasket with a new one, and screw Idle Control Valve back into its place. In models since 1999, de-electrify the electrical connector to the Idle Control Valve, loosen the screws, dismount the Idle Control Valve, change the old O-ring with a new one, and re-mount the Idle Control Valve, being careful to tighten the screws.