Fuel System:
* Fuel Pump Failure: The fuel pump might be failing intermittently or completely. This is a common cause of sudden engine shutdowns. Listen for the fuel pump whirring when you turn the key to the "on" position (before cranking). If you don't hear it, it's a strong suspect.
* Fuel Filter Clogging: A clogged fuel filter restricts fuel flow, leading to starvation and engine stalling.
* Clogged Fuel Injectors: Clogged injectors prevent proper fuel delivery.
* Fuel Pressure Regulator Issues: A malfunctioning regulator might not maintain the correct fuel pressure.
Ignition System:
* Distributor Cap/Rotor Problems: Cracks, corrosion, or wear in the distributor cap and rotor can disrupt the spark delivery to the spark plugs.
* Ignition Coil Failure: The coil provides the high voltage needed for ignition. A failing coil will cause misfires and eventually stalling.
* Spark Plugs/Wires: Worn, fouled, or damaged spark plugs or wires will prevent proper ignition.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position. A faulty sensor will prevent the engine from starting or running consistently.
* Cam Position Sensor (CMP): Similar to the CKP sensor, but for the camshaft. A fault here can cause similar problems.
Electrical System:
* Alternator Failure: If the alternator isn't charging the battery, the battery will eventually die, causing the engine to stall. Check your battery voltage.
* Battery Issues: A weak or dead battery can prevent starting.
* Faulty Wiring/Connections: Corrosion, loose connections, or damaged wiring anywhere in the system can disrupt power flow.
Other Potential Causes:
* Computer (ECU) Problems: The engine control unit might be malfunctioning, causing erratic behavior.
* Overheating: If the engine overheats, it might shut down as a safety measure. Check your coolant level.
* Mass Airflow Sensor (MAF) Issues: A faulty MAF sensor provides inaccurate air flow readings, leading to poor engine performance and stalling.
* Throttle Position Sensor (TPS): A bad TPS provides inaccurate throttle position data to the computer, causing issues.
Troubleshooting Steps:
1. Check the obvious: Battery voltage, coolant level, and fuel level.
2. Listen for the fuel pump: Turn the key to the "on" position (not cranking) and listen for the whirring sound.
3. Inspect the distributor cap and rotor: Look for cracks, corrosion, or wear.
4. Check spark plugs and wires: Inspect them for damage or fouling.
5. Have the battery and alternator tested: A simple test at an auto parts store can determine their condition.
Important Note: Without further diagnostics, it's impossible to pinpoint the exact cause. If you're not comfortable working on your car yourself, take it to a qualified mechanic for proper diagnosis and repair. They have the tools and expertise to properly diagnose the problem. Trying to fix it without proper knowledge could lead to further damage.
