* Idle Air Control (IAC) Valve: This valve regulates airflow at idle. A dirty or malfunctioning IAC valve can cause the engine to stall when idling, especially at stops.
* Throttle Position Sensor (TPS): This sensor tells the computer the throttle's position. A faulty TPS provides incorrect information, leading to erratic fuel delivery and stalling.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational speed. A failing CKP can cause the engine to misfire or stall, especially at low speeds.
* Mass Airflow Sensor (MAF): This sensor measures the amount of air entering the engine. A dirty or malfunctioning MAF can lead to improper fuel mixture and stalling.
* Fuel Pump: A weak or failing fuel pump might not provide sufficient fuel pressure at idle, resulting in stalling.
* Fuel Filter: A clogged fuel filter restricts fuel flow, causing similar issues to a weak fuel pump.
* Ignition System: Problems with the ignition coil, distributor (if equipped), spark plug wires, or spark plugs can lead to misfires and stalling, especially when the engine is under low load (at idle).
* Battery/Alternator: A weak battery or alternator unable to keep up with the electrical demand might cause the engine to stall. Test the battery voltage at idle and while revving the engine.
* Vacuum Leaks: Leaks in the vacuum system can disrupt the proper functioning of various engine components, including the idle control system, leading to stalling.
Troubleshooting Steps:
1. Check the Battery and Alternator: This is the easiest and safest place to start. Have the battery and charging system tested at an auto parts store or mechanic.
2. Inspect the IAC Valve: See if it's visibly dirty. Cleaning it might resolve the issue (look up a guide specific to your car's model).
3. Check for Vacuum Leaks: Visually inspect all vacuum lines for cracks or disconnections.
4. Have a Mechanic Scan for Diagnostic Trouble Codes (DTCs): A scan tool can read codes stored by the car's computer, providing clues about the malfunction. This is highly recommended.
Important Note: Without a proper diagnostic scan, it's difficult to pinpoint the exact cause. Trying to fix the problem without a proper diagnosis could lead to unnecessary repairs and expense. It's best to have a qualified mechanic diagnose the issue. The age of the car means multiple components might be wearing out simultaneously.
