1. Idle Air Control (IAC) Valve Issue: The IAC valve regulates the amount of air that bypasses the throttle plate when the engine is idling. A faulty or dirty IAC valve can cause the engine to idle erratically and may lead to stalling when the vehicle comes to a stop.
2. Faulty Oxygen Sensor: The oxygen sensor monitors the oxygen content in the exhaust gas and provides feedback to the engine control unit (ECU). A malfunctioning oxygen sensor can cause the engine to run rich or lean, resulting in rough idling and potential stalling.
3. Fuel System Problems: Issues such as a clogged fuel filter, a failing fuel pump, or a faulty fuel pressure regulator can disrupt the proper fuel delivery to the engine. This can cause irregular idling and engine stalling.
4. Vacuum Leak: A vacuum leak in the engine's intake system can lead to a lean air-fuel mixture, causing the engine to idle roughly and potentially stall when the vehicle decelerates or stops.
5. Throttle Body Issues: A dirty or malfunctioning throttle body can disrupt the proper airflow to the engine, leading to irregular idling and stalling.
6. Spark Plugs and Ignition System: Worn-out spark plugs, faulty ignition coils, or damaged spark plug wires can cause the engine to misfire, leading to rough idling and potential stalling.
7. Clogged Catalytic Converter: A blocked catalytic converter can restrict the exhaust flow and affect engine performance, causing rough idling and possible stalling in some cases.
8. Faulty Mass Air Flow (MAF) Sensor: The MAF sensor measures the amount of air entering the engine. If it's defective, it can disrupt the air-fuel ratio, resulting in rough idling and stalling problems.
9. Engine Mechanical Issues: In severe cases, internal engine problems like worn piston rings, faulty valves, or excessive carbon buildup can lead to rough idling and stalling.
To accurately identify the cause and address the problem, it's essential to have the car's engine and its systems inspected by a qualified mechanic or at a reputable automotive repair shop.
