What causes this violent engine vibration at idle? The whole car shakes. It runs smoothly otherwise when over idle rpm. Timing chain? Slight vibrations and rpm tremble on idle and stop light M120 V12 rough idle and vibration is this normal?, I have a Mercedes Benz W140 S600 with the M120 V12 engine., I know this engine is supposed to be very smooth, but mine has noticeable vibration at 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 Does Your Car Shake at Idle but Smooth Out While Driving? Here's Why