1. Vacuum leaks: Check for leaks in vacuum hoses or connections, which can cause a lean fuel mixture and rough idling.
2. Spark plugs: Worn or fouled spark plugs can affect engine performance and cause rough idling. Check the condition of the spark plugs and replace if needed.
3. Fuel injectors: Dirty or clogged fuel injectors can lead to uneven fuel delivery and rough idling. Consider servicing or replacing the fuel injectors.
4. Ignition coil: A faulty ignition coil can result in inconsistent ignition and rough idling. Check the ignition coil for proper functioning and replace if necessary.
5. Idle air control valve (IAC valve): The IAC valve regulates the airflow at idle speed. A faulty IAC valve can cause rough idling or stalling. Check and clean the valve, or replace it if needed.
6. Throttle body: A dirty throttle body can affect the airflow and idle quality. Clean the throttle body and check its functionality.
7. Oxygen sensor: A faulty oxygen sensor can provide incorrect feedback to the engine's fuel injection system, leading to a rough idle. Test the oxygen sensor and replace it if needed.
8. Fuel filter: A clogged fuel filter can restrict the flow of fuel to the engine, causing rough idling and fuel starvation. Replace the fuel filter regularly as per the maintenance schedule.
9. Compression issues: Low compression in the engine's cylinders can lead to poor combustion and rough idling. Perform a cylinder compression test to check the engine's compression and identify any problems.
10. Engine sensors: Various sensors, such as the coolant temperature sensor, manifold air pressure sensor, and throttle position sensor, provide crucial information to the engine control unit (ECU) for proper engine operation. Faulty sensors can affect the ECU's decision-making and result in rough idling.
It is recommended to have the vehicle inspected by a professional mechanic to accurately diagnose and fix the root cause of the rough idling issue.
