With the engine at operating temperature and an accurate tachometer connected: Center punch and drill (1/8" bit) the tamper proof plug located on the throttle housing. Remove the plug with a sheetmetal screw and pliers. Discard the plug and clean up any metal chips. Switch the ignition on - DO NOT START THE VEHICLE. Disconnect the stepper motor plug Switch ignition off Listen for click from EFI main relay (under the right front seat). Reconnect the stepper motor plug. Switch the ignition on - DO NOT START THE VEHICLE. Disconnect the stepper motor plug. Start the vehicle in neutral without touching the accelerator Adjust the base idle speed with a 3/16" Hex wrench to 550 to 650 RPM by turning the base idle screw. Turning counter clockwise will raise the speed and vice versa. Reconnect stepper motor plug. Switch ignition off. WAIT for main relay click Switch ignition on, start the engine and rev briefly to 2000 RPM Idle speed should stabilize at 665-735 RPM Install new tamper proof plug.