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 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 What could be the cause of engine vibration when idling? Customer states: small vibration., Meanwhile the engine mount: , If your car shakes while idling, clunks when shifting, or feels rough while driving, your engine mounts could be failing., Bad Why Does My Car Shake at Idle but Smooth Out While Driving? what's the issue with idle vibration at around 800 rpm?