Fuel System:
* Fuel Pump: A weak fuel pump might provide enough pressure for idling but not enough for the increased demand during acceleration. Listen for the fuel pump whine when you turn the key to the "on" position (before cranking). If it's weak or doesn't prime, it's a suspect. Fuel pressure testing is necessary for confirmation.
* Fuel Filter: A clogged fuel filter restricts fuel flow, similar to a weak pump. This is a cheap and easy component to replace.
* Fuel Injectors: Clogged or failing injectors can't deliver enough fuel under load. This usually requires professional diagnosis and potentially cleaning or replacement.
* EGR Valve: A stuck-open EGR valve can allow excessive exhaust gas into the intake, leading to a lean condition and stalling under acceleration. Inspect for proper operation and cleaning may be sufficient.
Ignition System:
* Ignition Coil: A failing ignition coil may not produce enough spark under load. This will cause misfires and stalling.
* Distributor Cap and Rotor (if applicable): Cracks or corrosion in these components can interrupt the spark delivery. Inspect for damage and replace if necessary.
* Spark Plugs and Wires: Worn spark plugs or faulty wires can lead to misfires, especially under acceleration. Inspect for wear and tear and replace as needed. Check the gap on the spark plugs.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational speed. A faulty sensor can cause erratic timing and stalling.
Air Intake System:
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor provides inaccurate air/fuel ratio readings to the computer, causing poor performance and stalling. Cleaning the MAF sensor (carefully!) is often the first step, but replacement may be necessary.
* Vacuum Leaks: Leaks in the intake system can lead to a lean air/fuel mixture, causing stalling. Inspect all vacuum hoses for cracks or disconnections.
* Throttle Position Sensor (TPS): A faulty TPS sensor provides incorrect throttle position information to the computer. This can result in poor idle and stalling under acceleration.
Other Possibilities:
* Transmission Issues (Automatic): In automatic transmissions, issues like low fluid level or a failing torque converter can cause stalling during acceleration. Check the transmission fluid level.
* Computer Problems (PCM): A faulty PCM (Powertrain Control Module) can cause various issues, including this symptom. This is a less likely but possible cause and usually requires professional diagnostics.
Troubleshooting Steps:
1. Start with the easy stuff: Check the fuel filter, spark plugs, wires, and vacuum hoses.
2. Listen for the fuel pump: Make sure it's priming correctly.
3. Check engine codes: Use an OBD-II scanner to retrieve any diagnostic trouble codes (DTCs). These codes can point you in the right direction.
4. Visual inspection: Look for anything obviously wrong, like loose connections, broken wires, or damaged components.
If you're not comfortable working on your vehicle yourself, take it to a qualified mechanic for diagnosis and repair. Providing the mechanic with any error codes you find will significantly speed up the process.
