Fuel System Issues:
* Clogged Fuel Filter: A dirty fuel filter restricts fuel flow, leading to stalling or difficulty staying running, especially under load.
* Fuel Pump Failure: A weak or failing fuel pump can't supply enough fuel to the engine. This is common in older vehicles.
* Bad Fuel Pressure Regulator: This regulates fuel pressure; a malfunction can lead to inconsistent fuel delivery.
* Clogged Fuel Injectors: Clogged injectors prevent proper fuel atomization, leading to poor combustion and stalling.
* Low Fuel Level: Sounds obvious, but a low fuel level can sometimes cause problems, especially if the pickup in the tank is getting near the bottom.
Ignition System Problems:
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the engine's rotational position; a faulty one can prevent proper ignition timing or even starting.
* Cam Position Sensor (CMP Sensor): Similar to the CKP sensor, a bad CMP sensor disrupts ignition timing.
* Ignition Coil(s): A failing coil won't provide sufficient spark to one or more cylinders.
* Spark Plugs & Wires: Worn or damaged spark plugs or wires can lead to misfires and stalling. Especially consider this given the age of the vehicle.
* Ignition Control Module (ICM): This module controls the ignition system; a failure will cause significant problems.
Other Potential Causes:
* Mass Airflow Sensor (MAF Sensor): A faulty MAF sensor provides inaccurate air/fuel mixture readings to the computer, leading to poor running or stalling.
* Throttle Position Sensor (TPS): This sensor tells the computer the throttle position; a malfunction can cause erratic idling and stalling.
* Vacuum Leaks: Leaks in the vacuum system can disrupt engine operation. Look for cracked hoses or connections.
* Computer Problems (PCM/ECM): While less common, a failing PCM (Powertrain Control Module) or ECM (Engine Control Module) can cause a wide range of issues, including stalling.
* Alternator: If the alternator isn't charging the battery, the engine might die once the battery is drained.
* Dirty or Failing Idle Air Control (IAC) Valve: This regulates air flow at idle; if it's dirty or failing, the engine might stall.
Troubleshooting Steps:
1. Check the basics: Fuel level, obvious vacuum leaks, and battery voltage.
2. Listen to the engine: Unusual noises (knocking, ticking) can point to specific problems.
3. Check engine codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored by the computer. This is the single most important step.
4. Visual inspection: Look for anything obviously wrong – loose wires, damaged hoses, etc.
Because there are so many possibilities, it's highly recommended to get the vehicle scanned for diagnostic trouble codes using an OBD-II scanner. This will give you a much better starting point for diagnosis. If you're not comfortable working on cars, take it to a mechanic. Trying to troubleshoot these issues without the right tools and knowledge can be time-consuming and potentially frustrating.
