An idle air control valve, also called an idle air sensor control motor, is an electrically operated valve that controls the amount of air that bypasses the throttle plate in cars with a fuel injection system [source: Autozone]. This causes the idling speed of the engine to change as needed.Click to see full answer. Keeping this in view, what happens when the idle air control valve goes bad?One of the most common symptoms associated with a problematic idle air control valve is irregular idle speed. Read More...