Fuel System Problems:
* Low fuel pressure: The fuel pump may be failing, the fuel filter may be clogged, or there might be a leak in the fuel lines. This means the engine isn't getting enough fuel to stay running at idle.
* Clogged fuel injectors: Dirty injectors can't deliver fuel efficiently, leading to a rough idle and potential stalling.
* Bad fuel pump relay: The relay controls the fuel pump's power; a faulty relay prevents the pump from operating.
Ignition System Problems:
* Failing ignition coil: This component provides the spark needed to ignite the fuel-air mixture. A weak or failing coil can cause misfires, especially at idle when the engine's demands are lower.
* Worn spark plugs or wires: These components deliver the spark; wear and tear can lead to weak or inconsistent sparking.
* Crankshaft position sensor (CKP) or camshaft position sensor (CMP) issues: These sensors tell the engine's computer the position of the crankshaft and camshaft. Faulty sensors lead to incorrect timing and potential stalling.
Air Intake System Problems:
* Vacuum leaks: Leaks in the intake manifold or vacuum hoses disrupt the air-fuel mixture, making idling difficult.
* Dirty air filter: A severely clogged air filter restricts airflow, leading to a lean air-fuel mixture and potential stalling. This is less likely to cause stalling than the other problems listed, but can contribute.
Other Potential Causes:
* Alternator problems: If the alternator isn't charging the battery, the car will eventually die, especially when idling and drawing more power than the battery can supply.
* Throttle body issues: A dirty or malfunctioning throttle body can disrupt the air intake, leading to stalling.
* Computer (ECM/PCM) problems: The engine control module (ECM) or powertrain control module (PCM) controls many engine functions. A faulty module can lead to a variety of problems, including stalling.
* Idle air control (IAC) valve problems: This valve regulates the amount of air entering the engine at idle. A faulty IAC valve can cause erratic idling or stalling.
* Low battery: A weak battery might not have enough power to keep the engine running, especially at idle.
It's important to have a mechanic diagnose the problem. Many of these issues have overlapping symptoms, and attempting to fix it yourself without proper knowledge could lead to further damage or injury.
