why does my 2000 GMC Jimmy car vibrate?

And it just started making that noise today.

A vibrating car can be caused by various factors, and diagnosing the issue without physically inspecting the vehicle can be challenging. However, I can provide some common reasons why your 2000 GMC Jimmy might be experiencing vibrations: 1. Engine-related issues: Vibrations at idle could be caused by problems with the engine, such as misfiring spark plugs, a faulty ignition coil, or an issue with the engine mounts. 2. Exhaust system problems: A loose or damaged exhaust system component can create vibrations and unusual sounds. 3. Transmission issues: Problems with the transmission, such as a worn-out torque converter or a faulty transmission mount, can lead to vibrations. 4. Suspension and wheel-related problems: Worn-out suspension components, unbalanced wheels, or damaged tires can cause the vehicle to vibrate, especially when stopped or at low speeds. 5. Air conditioning system: The black box you mentioned could be part of the HVAC system, and if it's malfunctioning, it might cause vibrations or unusual sounds. While your acquaintance suggested it might be the air door control, it's always best to have a qualified mechanic inspect the vehicle thoroughly. They can identify the root cause of the issue and provide a proper diagnosis. Ignoring potential problems can lead to more significant issues down the road and may compromise the safety and performance of your vehicle. To get a better idea of what might be causing the vibration, consider taking your GMC Jimmy to a reputable auto repair shop for a professional inspection. Explain the symptoms you are experiencing, including the unusual sound from the black box behind the glove compartment, to help the mechanic narrow down the possible sources of the problem.