- Idle Air Control Valve (IACV): The IACV regulates the amount of air that bypasses the throttle body when the engine is idling. If the IACV is faulty, it can cause the engine to stall when you take your foot off the gas pedal.
- Throttle Body: The throttle body controls the amount of air that flows into the engine. If the throttle body is dirty or damaged, it can cause the engine to stall.
- Manifold Absolute Pressure (MAP) Sensor: The MAP sensor measures the air pressure in the intake manifold. If the MAP sensor is faulty, it can send incorrect signals to the engine's computer, which can cause the engine to stall.
- Fuel Pressure: Low fuel pressure can cause the engine to stall. Check the fuel pressure to ensure it is within the specified range.
- Vacuum Leaks: Vacuum leaks can cause the engine to run lean, which can lead to stalling. Inspect the vacuum lines for any leaks.
Diagnosis and Repair:
1. Check the IACV: Start the engine and let it idle. Remove the IACV from the throttle body and inspect it for any damage or debris. If the IACV is faulty, replace it.
2. Clean the Throttle Body: Remove the throttle body from the engine and clean it with throttle body cleaner. Make sure to clean the IACV passage while cleaning the throttle body.
3. Check the MAP Sensor: Disconnect the MAP sensor and start the engine. If the engine idles smoothly, the MAP sensor may be faulty. Replace the MAP sensor if necessary.
4. Check the Fuel Pressure: Connect a fuel pressure gauge to the fuel rail and check the fuel pressure. If the fuel pressure is low, the fuel pump or fuel filter may be faulty. Replace the faulty component if necessary.
5. Check for Vacuum Leaks: Inspect the vacuum lines for any leaks. If you find any leaks, repair them.
If you have tried all of the above and the engine is still stalling, you may need to take it to a mechanic for further diagnosis and repair.
