Car Vibrates When Idle: Major Causes and More dubizzle What could be the cause of engine vibration when idling? What Causes Your Car to Vibrate While Idling? WHY YOUR CAR SHAKES WHEN IDLING If your car feels smooth while driving but starts vibrating or shaking at a stoplight, something isn't right. At idle, the engine runs at its Why Does Your Engine Vibrate at Idle? Noticing your engine shaking or vibrating while idling? This could mean something isn't right under the hood. Here's what might be causing it and how Steering wheel vibration while idle.