* Fuel Pump: A weak fuel pump might struggle to supply enough fuel under increased demand. This is a very common cause of stalling under load.
* Fuel Filter: A clogged fuel filter will restrict fuel flow, leading to similar symptoms.
* Clogged Catalytic Converter: A severely restricted catalytic converter can back up exhaust gases, choking the engine and causing stalling, particularly under load.
* Mass Airflow Sensor (MAF) or Throttle Position Sensor (TPS): These sensors tell the engine's computer how much air is entering, and a faulty sensor can cause incorrect fuel mixtures, leading to stalling. Dirty MAF sensors are particularly problematic.
* Ignition System: Issues with the ignition coil, spark plug wires, distributor cap (if equipped), or spark plugs themselves can cause misfires, leading to stalling, especially under load when the engine needs more power.
* Vacuum Leaks: Leaks in the vacuum system can disrupt the fuel/air mixture, leading to poor performance and stalling.
* Throttle Body: A dirty or malfunctioning throttle body can impede airflow, causing similar problems.
Troubleshooting Steps (in order of likelihood and ease):
1. Check the fuel filter: This is cheap and easy to replace. If it's clogged, that's likely your problem.
2. Inspect the fuel pump (if possible): Listen for the fuel pump whirring when you turn the key to the "on" position (before cranking). A weak or failing pump might make a weaker sound or not be heard at all. This is more difficult to assess directly without specialized tools.
3. Check the air filter: A severely clogged air filter will restrict airflow, similar to a clogged fuel filter.
4. Check the spark plugs and wires: Look for signs of damage, wear, or fouling. Replacing them is relatively inexpensive.
5. Clean the throttle body: A build-up of grime can restrict airflow. Cleaning it is often straightforward.
6. Have the MAF and TPS sensors checked: This often requires specialized tools or a professional mechanic to properly diagnose.
Important Note: Without a proper diagnostic scan, pinpointing the exact cause is difficult. A professional mechanic with OBD-II diagnostic equipment can read codes from the engine's computer and quickly narrow down the possibilities. Trying to fix the problem without diagnostics might lead to unnecessary parts replacement and expense.
