* Idle air control valve (IACV) problems. The IACV is a valve that controls the amount of air that bypasses the throttle body. If the IACV is faulty, it can cause the engine to idle at a high or low speed, or even to stall.
* Throttle body problems. The throttle body is a valve that controls the amount of air that flows into the engine. If the throttle body is dirty or damaged, it can cause the engine to idle at a high or low speed, or even to stall.
* Vacuum leaks. Vacuum leaks can cause the engine to idle at a high or low speed, or even to stall.
* Fuel system problems. Fuel system problems, such as a clogged fuel filter or a faulty fuel pump, can cause the engine to idle at a high or low speed, or even to stall.
* Electrical problems. Electrical problems, such as a faulty battery or a damaged alternator, can cause the engine to idle at a high or low speed, or even to stall.
If your car is idling high and low, and then eventually turning off, it's important to take it to a qualified mechanic to diagnose the problem. The mechanic will be able to identify the cause of the problem and recommend the best course of action.
