* Idle air control valve (IACV) problems. The IACV is responsible for controlling the amount of air that bypasses the throttle plate when the engine is idling. If the IACV is faulty, it can cause the engine to idle too high or too low, or to stall.
* Vacuum leaks. Vacuum leaks can cause the engine to idle rough or stall. Vacuum leaks can occur anywhere in the engine, but they are most common in the intake manifold, throttle body, and vacuum hoses.
* Fuel injector problems. Faulty fuel injectors can cause the engine to idle rough or stall. Fuel injector problems can be caused by a variety of factors, including dirt or debris in the fuel injector, a faulty injector solenoid, or a bad electrical connection.
* Spark plug problems. Faulty spark plugs can cause the engine to idle rough or stall. Spark plug problems can be caused by a variety of factors, including worn spark plugs, a bad spark plug wire, or a bad distributor cap.
* Timing problems. Ignition timing problems can cause the engine to idle rough or stall. Ignition timing problems can be caused by a variety of factors, including a worn timing belt or chain, a bad distributor, or a bad ignition module.
If your car is not idling properly, it is important to have it diagnosed by a qualified mechanic. The mechanic will be able to identify the cause of the problem and recommend the appropriate repairs.
