* Crank Position Sensor (CKP): This is a common culprit in these cars when they have starting but no running issues. A failing CKP sensor can provide intermittent or inaccurate signals to the computer, preventing the engine from staying running. It's relatively easy to access and replace, and relatively inexpensive.
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor can lead to a lean fuel condition, causing the engine to stall. Try cleaning the MAF sensor with MAF sensor cleaner (following the instructions carefully). If cleaning doesn't work, replacement may be necessary.
* Idle Air Control (IAC) Valve: The IAC valve controls the idle speed. A dirty or faulty IAC valve can cause the engine to stall, especially at idle. Cleaning it (again, carefully) is worth a try. Replacement is relatively inexpensive.
* Fuel Pressure Regulator: While you changed the fuel filter, a faulty fuel pressure regulator could be causing inconsistent fuel pressure. This requires a fuel pressure gauge to diagnose accurately.
* Throttle Position Sensor (TPS): A faulty TPS can provide incorrect information to the ECM, leading to running problems. Testing this usually requires a multimeter.
* Ignition System: While it starts, check for weak spark. Inspect the ignition coil, spark plug wires, and distributor cap and rotor (if applicable - LT1 engine has coil packs). A weak spark might be enough to start the engine, but not keep it running.
* Vacuum Leaks: Check all vacuum lines for cracks or leaks. A significant leak can disrupt the air/fuel mixture.
* PCM (Powertrain Control Module) issues: While less likely, a problem with the PCM itself is a possibility. This is a more complex issue requiring diagnostic tools.
Troubleshooting Steps:
1. Check for error codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the PCM. These codes can point directly to the problem.
2. Listen for unusual sounds: Are there any clicking, ticking, or hissing sounds coming from the engine compartment?
3. Check for obvious issues: Look for loose connections, damaged wiring, or anything out of place.
Before doing anything major:
* Double-check fuel filter installation: Ensure the fuel filter was installed correctly and that there are no leaks.
* Check fuel pressure: As mentioned above, use a fuel pressure gauge to verify adequate fuel pressure.
If you're not comfortable working on your car yourself, take it to a mechanic. These are just some of the possibilities; a professional diagnosis is often the most efficient and reliable way to solve the problem.
