1. Make sure the engine is warm.
2. Locate the idle speed adjustment screw on the throttle body. It is usually a black plastic screw with a slotted head.
3. Start the engine and let it run for a few minutes to warm up.
4. Connect a tachometer to the engine.
5. Use a flat-blade screwdriver to turn the idle speed adjustment screw until the engine is idling at the desired RPM. The specified idle speed for the 1989 Chrysler LeBaron 2.5L is 700 ±50 RPM.
6. Once the idle speed is set, turn off the engine and disconnect the tachometer.
Note: If the idle speed adjustment screw is turned too far in one direction, it can cause the engine to stall or surge. If this happens, turn the screw back in the opposite direction until the engine idles smoothly.
