Car Shaking at Idle: 8 Causes and When to See a Mechanic (2026 Guide) 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 Is your car vibrating when idle? Here's when you should be worried 2015 car vibrating at idle, RPM 500 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 Why Is My Car Shaking When Idle? AutoTechIQ