Fuel System:
* Clogged Fuel Filter: A dirty fuel filter restricts fuel flow, especially under increased demand (when you accelerate). This is a cheap and easy check.
* Fuel Pump: A failing fuel pump might not be able to supply enough fuel under pressure when you accelerate. You might hear a whining sound from the fuel pump when the key is turned on (but not started) if it's weak.
* Clogged Fuel Injectors: Clogged injectors prevent proper fuel atomization and delivery. This is more likely if the problem is gradual and/or accompanied by rough running even at idle.
* Bad Mass Airflow Sensor (MAF) Sensor: The MAF sensor measures the amount of air entering the engine. A faulty sensor can provide inaccurate readings, leading to a lean fuel mixture and stalling.
* Low Fuel Pressure: A pressure regulator problem can cause insufficient fuel pressure to the injectors.
Ignition System:
* Crankshaft Position Sensor (CKP): This sensor tells the engine's computer where the crankshaft is. A faulty CKP will cause the engine to misfire or stall, especially under load.
* Cam Position Sensor (CMP): Similar to the CKP, but for the camshaft. A faulty CMP will also cause misfires and stalling.
* Ignition Coil(s): Weak or failing ignition coils won't provide enough spark to ignite the air/fuel mixture consistently.
* Spark Plugs/Wires: Worn-out spark plugs or faulty wires can lead to misfires and stalling.
Vacuum Leaks:
* Vacuum Hose Leaks: A significant vacuum leak can disrupt the engine's ability to control the air/fuel mixture, causing stalling. These can be hard to find.
Other Possibilities:
* Throttle Position Sensor (TPS): A faulty TPS provides incorrect information to the engine computer about the throttle position, leading to erratic fuel delivery.
* Engine Control Module (ECM): Although less common, a failing ECM can cause a variety of problems, including stalling.
Troubleshooting Steps:
1. Check the obvious: Start with the easiest and cheapest things: fuel filter, spark plugs, and wires. Visually inspect for any obvious damage or wear.
2. Listen for unusual sounds: Pay attention to any whining from the fuel pump or unusual clicking from the ignition system.
3. Check codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the ECM. This can pinpoint the likely cause.
4. Professional Diagnosis: If you're not comfortable working on your car yourself, take it to a mechanic for proper diagnosis and repair. They have tools to test fuel pressure, check sensor readings, and isolate the problem more efficiently.
Remember safety first! Disconnect the negative battery terminal before working on any electrical components.
