Diagnose and Fix Rough Car Idle Main Causes For Shaking Vibrating While at a Stop YouTube Solve Rough Idle Now: Main Causes of Shaking at a Stop Vibrating while idling in drive 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 Ever felt your car shaking or vibrating while sitting at a red light? That rough idle is a classic symptom, but the cause isn't always obvious. As shown in the comparison, Is your car vibrating when idle? Here's when you should be worried