Why does your car make a popping noise when its shut off?

The most likely cause of a popping noise when your car is shut off is the exhaust system. As the engine cools down, the metal components in the exhaust system contract and make a popping sound. This is especially common in older cars with less insulation around the exhaust system.

Another possible cause of a popping noise when your car is shut off is the fuel injection system. When the engine is turned off, the fuel injectors stop working and the fuel pressure in the system drops. This can cause the fuel to vaporize and create a popping sound. This is more common in cars with direct fuel injection systems.

In most cases, a popping noise when your car is shut off is not a cause for concern. However, if the noise is accompanied by other symptoms, such as a loss of power or engine performance, it's best to have your car inspected by a qualified mechanic.