Common Causes of Car Shaking at Idle and How to Fix It

[Beth Murphy]

Car shaking at idle but smoothing out while driving is a common issue many drivers face. It can be annoying, but understanding the causes can help you address it effectively. Here are some of the most common reasons for this problem:

1. Worn Spark Plugs or Ignition System Issues
   If your car shakes at idle but smooths out while driving, it could be due to worn-out spark plugs or ignition coils. These components are crucial for proper combustion, and when they wear down, your engine may misfire, causing vibrations at idle.

2. Dirty Fuel Injectors
   Fuel injectors that are clogged or dirty can disrupt the fuel-air mixture in the engine, leading to rough idling. This problem can be resolved with a professional cleaning or injector replacement.

3. Vacuum Leaks
   A vacuum leak can also cause rough idling. The engine might be getting more air than it should, affecting the air-fuel ratio and resulting in shaking at idle. Identifying and repairing the leak will stop the shaking.

How to Fix It

• Check and replace spark plugs if necessary.
• Clean or replace the fuel injectors.
• Inspect and repair any vacuum leaks.

By addressing these issues, your car should idle smoothly once again.