1. Locate the idle air control valve (IACV). It is usually located on the throttle body.
2. Disconnect the electrical connector from the IACV.
3. Use a 5/16-inch Allen wrench to turn the IACV screw clockwise to increase the idle speed or counterclockwise to decrease it.
4. Reconnect the electrical connector to the IACV.
5. Start the engine and let it idle for a few minutes.
6. Check the idle speed with a tachometer. The desired idle speed for a Jeep Grand Cherokee Laredo is between 600 and 700 RPM.
7. If necessary, repeat steps 3-6 until the desired idle speed is achieved.