Possible Causes:
* Fuel System:
* Fuel pump: A weak or failing fuel pump might not supply enough fuel to keep the engine running once it's started. Listen for the fuel pump whirring when you turn the key to the "on" position (before cranking). A weak whir or no whir is a strong indicator.
* Fuel filter: A clogged fuel filter restricts fuel flow.
* Fuel pressure regulator: A faulty regulator could be leaking fuel pressure, preventing sufficient fuel delivery. This often requires a pressure gauge test.
* Clogged fuel injectors: Dirty injectors might not spray fuel properly.
* Fuel tank issues: A problem with the fuel pickup in the tank (e.g., debris blocking it) could prevent fuel from reaching the pump.
* Ignition System:
* Distributor cap and rotor: Worn or cracked components can lead to poor ignition. Inspect for cracks, corrosion, or worn contacts.
* Ignition coil: A failing coil won't provide the necessary spark.
* Spark plugs and wires: Worn or damaged spark plugs or wires will result in weak or no spark.
* Air Intake System:
* Mass airflow sensor (MAF): A dirty or faulty MAF sensor provides incorrect information to the engine computer, leading to poor fuel mixture.
* Vacuum leaks: Leaks in the vacuum lines can disrupt engine operation. Listen for hissing sounds near the intake manifold.
* Throttle position sensor (TPS): A faulty TPS sends incorrect throttle position information to the computer.
* Engine Components:
* Crankshaft position sensor (CKP): A faulty CKP sensor prevents the engine from receiving proper timing signals.
* Camshaft position sensor (CMP): Similar to the CKP sensor, a faulty CMP affects timing.
* Idle air control valve (IAC): This valve controls idle speed. A dirty or faulty IAC can cause stalling.
* Other:
* Battery: A weak battery may not provide enough power to maintain engine operation.
* Alternator: A failing alternator might not charge the battery, leading to a stall.
* Computer issues: A problem with the engine control module (ECM) can cause erratic engine behavior.
Troubleshooting Steps:
1. Check the obvious: Make sure the battery is charged and the terminals are clean and tight.
2. Listen for the fuel pump: As mentioned above, this is a quick check for a common problem.
3. Inspect the distributor cap and rotor (if applicable): Look for any obvious signs of wear or damage.
4. Check for vacuum leaks: Listen carefully for hissing sounds around the intake manifold.
5. Consider a code scan: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored by the ECM. This is a crucial step.
6. Check fuel pressure (requires a gauge): This will help determine if the fuel pump and regulator are working correctly.
Important Note: Without more specific symptoms (e.g., engine running rough before stalling, any warning lights illuminated on the dashboard), pinpointing the exact cause is difficult. The best approach is to systematically check the components listed above, starting with the most likely causes. If you're not comfortable working on your car yourself, take it to a qualified mechanic for diagnosis and repair.
