* Fuel Pump: The fuel pump is the most common suspect. It could be failing intermittently, providing fuel sometimes but not others. This is especially likely if the problem occurs more frequently when the tank is low (less pressure). A failing pump might also make a whining noise when the key is turned on before starting.
* Fuel Filter: A clogged fuel filter restricts fuel flow. If it's severely clogged, the engine might starve for fuel, even with a functioning pump. These are inexpensive and relatively easy to replace.
* Fuel Pressure Regulator: This regulator maintains consistent fuel pressure in the system. A faulty regulator could lead to insufficient pressure, preventing the engine from getting enough fuel.
* Crankshaft Position Sensor (CKP): This sensor tells the engine's computer where the crankshaft is in its rotation. A faulty CKP sensor will prevent the engine from starting or running smoothly, mimicking various symptoms, including a lack of fuel.
* Camshaft Position Sensor (CMP): Similar to the CKP sensor, a faulty CMP sensor disrupts engine timing and can cause the engine to stall.
* Ignition System: While less likely to mimic fuel starvation, problems with the ignition coil, ignition module, distributor cap, rotor, or spark plugs can cause the engine to cut out unexpectedly.
* Mass Airflow Sensor (MAF): This sensor measures the amount of air entering the engine. A faulty MAF sensor can cause the engine to run lean (too much air, not enough fuel), leading to stalling or misfires.
* Throttle Position Sensor (TPS): This sensor tells the computer the throttle position. A faulty TPS can lead to inconsistent fuel delivery.
* Wiring Issues: Corroded, loose, or damaged wiring in the fuel system or engine control system can interrupt the flow of electricity and fuel, causing intermittent problems.
* Pick-up Tube (in the tank): While less common, the fuel pickup tube at the bottom of the tank can become clogged with debris or rust, preventing fuel from reaching the pump.
Troubleshooting Steps:
1. Check the fuel level: While you say there's fuel, verify the amount and check for any obvious debris in the fuel tank.
2. Listen for the fuel pump: Turn the key to the "on" position (without starting) and listen for a brief hum from the fuel pump near the fuel tank. If you don't hear it, the pump might be the problem.
3. Check the fuel filter: Inspect it for clogging. This is a cheap and easy check to eliminate a possible cause.
4. Have a mechanic check fuel pressure: This requires a fuel pressure gauge to measure the pressure in the fuel rail. This will determine if the fuel pump and regulator are working correctly.
5. Check engine codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the vehicle's computer. These codes can point to the specific component causing the issue.
It's highly recommended to have a qualified mechanic diagnose the problem. Trying to troubleshoot this without proper tools and experience could lead to further damage or misdiagnosis. The intermittent nature of the problem makes pinpoint diagnosis difficult without professional tools and expertise.
