1. Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer where the crankshaft is in its rotation. If it's faulty, the computer won't know when to ignite the fuel, causing the engine to die. This is a very common cause of this symptom.
2. Cam Position Sensor (CMP Sensor): Similar to the CKP sensor, but for the camshaft. A faulty CMP sensor will disrupt the timing of the fuel injection and ignition, leading to a sudden stall.
3. Fuel Pump: The pump might be delivering fuel initially, but failing to maintain sufficient pressure. This can cause the engine to stop after starting. Listen for the fuel pump's whine when you turn the key to the "on" position (before cranking). If you don't hear it, that's a strong indication of a problem.
4. Ignition Coil(s): These deliver the spark to the spark plugs. A failing coil can initially work but then fail under load, causing the engine to shut down.
5. Mass Airflow Sensor (MAF Sensor): This sensor measures the amount of air entering the engine. A dirty or faulty MAF sensor can send incorrect information to the computer, leading to a lean condition and stalling. Cleaning it is often a good first step.
6. Throttle Position Sensor (TPS): This sensor tells the computer the throttle position. A faulty TPS can cause erratic fuel delivery and stalling.
7. Vacuum Leaks: A large vacuum leak can starve the engine of air, causing it to stall. Inspect all vacuum hoses and connections.
8. Fuel Filter: A clogged fuel filter restricts fuel flow, but this is less likely to cause immediate stalling after starting unless it's completely blocked.
9. Computer Issues (PCM/ECM): While less common, a problem with the Powertrain Control Module (PCM) or Engine Control Module (ECM) can cause this type of issue. This requires a diagnostic scan tool.
Troubleshooting Steps:
1. Listen for the fuel pump: As mentioned above, listen for the fuel pump prime when you turn the key to the "on" position.
2. Check for error codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the computer's memory. This is crucial for pinpointing the problem. Auto parts stores often offer free code reading.
3. Inspect visually: Check for obvious things like loose connections, frayed wires, cracked vacuum hoses, and anything that looks out of place.
4. Start with the easy checks: Clean the MAF sensor (carefully, following instructions).
5. Consider professional help: If you're not comfortable working on your vehicle yourself, take it to a trusted mechanic. The cost of a professional diagnosis will likely be less than replacing parts randomly.
Important Note: Safety first! Always disconnect the negative battery terminal before working on any electrical components in your vehicle.
Don't just start replacing parts; systematically diagnose the problem based on the information gathered. An OBD-II scan is your best first step for finding the source of the issue.
