my car give a small vibration and this rpm but if I raise it just below 1000 I don't feel it any ideas what cause this at idle motor mounts brand new even with a fresh tune up it still happens. any 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 Causes Your Car to Vibrate While Idling? Is your car vibrating when idle? Here's when you should be worried