Is your car vibrating when idle? Here's when you should be worried 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 SOME ENGINES IDLE ROUGHER THAN OTHERS Some cars idle like a sewing machine others shake, pulse, and sound angry even when standing still. That difference is all about engine 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