Car Engine Shuts Off When Idle

What is Idle?

Idle is a state of an engine in which it is running without being connected to a load. In a car, this means that the engine is running but the transmission is in neutral and the brakes are not applied.

Why Does My Car Engine Shut Off When Idle?

There are a few reasons why your car engine might shut off when idle. The most common reasons include:

Idle air control valve (IACV) is faulty. The IACV is responsible for regulating the amount of air that enters the engine at idle. If the IACV is faulty, it can cause the engine to stall when idle.
Throttle position sensor (TPS) is faulty. The TPS is responsible for telling the engine how much throttle is being applied. If the TPS is faulty, it can cause the engine to stall when idle.
Mass air flow sensor (MAF) is faulty. The MAF is responsible for measuring the amount of air that enters the engine. If the MAF is faulty, it can cause the engine to stall when idle.
Vacuum leak. A vacuum leak can cause the engine to stall when idle because it allows unmetered air to enter the engine. This can cause the engine to run lean, which can lead to stalling.

How to Fix a Car Engine That Shuts Off When Idle

If your car engine is shutting off when idle, there are a few things you can do to try to fix it.

Check the IACV. The IACV is located on the throttle body. You can check it by disconnecting it and seeing if the engine idles smoothly. If the engine idles smoothly with the IACV disconnected, then the IACV is faulty and needs to be replaced.
Check the TPS. The TPS is located on the throttle body. You can check it by using a multimeter to measure the voltage at the TPS connector. The voltage should be between 0.5 and 4.5 volts. If the voltage is not within this range, then the TPS is faulty and needs to be replaced.
Check the MAF. The MAF is located in the intake manifold. You can check it by using a multimeter to measure the voltage at the MAF connector. The voltage should be between 1 and 5 volts. If the voltage is not within this range, then the MAF is faulty and needs to be replaced.
Check for vacuum leaks. You can check for vacuum leaks by using a smoke machine. A smoke machine will pump smoke into the intake manifold and any vacuum leaks will be visible as smoke escaping from the engine. If you find any vacuum leaks, you will need to repair them.

Conclusion

If you are having problems with your car engine shutting off when idle, there are a few things you can do to try to fix it. By following the steps outlined in this article, you can hopefully get your car running smoothly again.