Ford Expedition humming noise from intake due to faulty idle air control valve on Ford Expedition

Some Ford Expedition owners report experiencing a humming noise from the intake, often attributed to a faulty idle air control valve. This noise is typically noticeable when starting the vehicle cold and may resemble a horn, particularly at idle. While tapping on the idle air control valve can temporarily alleviate the sound, many owners find that replacing the valve is necessary for a permanent solution. Accelerating the vehicle may stop the noise momentarily, but it often returns once the vehicle is back at idle. Even after replacement, some owners still hear the humming, which could indicate a potential issue with the manifold. Additionally, the noise can be described as loud and similar to a leaf blower or vacuum cleaner, echoing through the intake duct. To diagnose the problem, some owners disconnect the electrical connector or lightly tap on the valve to confirm if it is the source of the noise.