- Vacuum leaks: A vacuum leak can cause the engine to run lean, which can lead to rough idling. Check for any leaks in the vacuum lines, especially around the intake manifold and throttle body.
- Dirty fuel injectors: Dirty fuel injectors can cause the engine to run rich, which can also lead to rough idling. Try using a fuel injector cleaner or having the injectors professionally cleaned.
- Spark plug wires: Worn or damaged spark plug wires can cause the engine to misfire, which can lead to rough idling. Check the spark plug wires for any signs of damage, and replace them if necessary.
- Distributor cap and rotor: A worn or damaged distributor cap or rotor can also cause the engine to misfire, which can lead to rough idling. Check the distributor cap and rotor for any signs of damage, and replace them if necessary.
- Fuel pump: A weak fuel pump can cause the engine to run lean, which can lead to rough idling. Check the fuel pressure to see if it is within the recommended range. If the fuel pressure is low, the fuel pump may need to be replaced.
- Oxygen sensor: A faulty oxygen sensor can cause the engine to run rich or lean, which can lead to rough idling. Check the oxygen sensor to see if it is functioning properly. If the oxygen sensor is faulty, it will need to be replaced.
- Idle air control valve: A dirty or faulty idle air control valve can cause the engine to idle roughly. Clean the idle air control valve and check it to see if it is functioning properly. If the idle air control valve is faulty, it will need to be replaced.
