The idle air-control valve is designed to regulate the idle on your Ford car or truck. A malfunctioning idle air-control valve can cause too much or too little air to flow through your vehicle's intake and cause it to idle high, low or even stall out. Idle air-control valve problems are typically not serious in terms of affecting your vehicle's operation, but they can be a nuisance.
Shorts in the idle air-control valve's electrical wiring and circuits have been known to cause the IACV to malfunction in Ford vehicles. Electrical problems with the IACV have the potential to cause the vehicle to idle poorly or not at all due to too little air coming through the valve. Typically, these kinds of issues will cause the vehicle to generate error codes and your check-engine-light on the dashboard may illuminate.
Vehicles that spend a significant of time idling -- such as police cars or vehicles that are regularly driven in stop-and-go rush-hour traffic -- are more inclined to suffer idle air-control valve failures. These vehicle's IACVs undergo an unusually high amount of use and the components will break down more quickly than usual.
It is possible for your vehicle's engine to develop an air leak in its manifold or throttle body and get too much air flow coming through. In this instance, the power-train control module will tell the IACV to close off airflow in an effort to regulate the amount of air traveling through the engine and the speed of the idle.
Idle speed increases with air flow.
