Car Shakes When Idle

It can be alarming when your car suddenly begins to shake or vibrate when sitting at a stoplight or when idle. While it may seem like a major issue, a shaking idle is often caused by minor problems that can be easily fixed. Here are some of the most common reasons a car shakes when idle.

Engine Misfires

One of the most common causes of idle shaking is an engine misfire. This occurs when one or more of the cylinders fails to fire properly. Misfires can be caused by faulty spark plugs, bad wiring, or issues with the fuel injectors or supply. Replacing spark plugs and wires is often an easy fix.

Dirty Fuel Injectors

Over time, fuel injectors can become clogged with deposits that prevent them from spraying fuel properly. This can make the engine run rough and shaky at idle. Using fuel injector cleaners or having a shop professionally clean the injectors can help resolve this issue.

Worn Engine Mounts

Engine mounts hold the engine firmly in position and reduce vibrations. When these mounts become worn out, it allows more engine shaking and vibration to transfer to the chassis. Replacing cracked or deteriorated engine mounts will prevent excessive shaking.

Loose/Damaged Motor Supports

Issues like loose motor mounts, a broken transmission mount, damaged control arm bushings, or worn ball joints can also allow more engine vibration and shaking. Inspect all engine/transmission supports and replace any loose or damaged parts.

Ignition Timing Issues

Incorrect ignition timing can make the engine misfire and run unevenly. Improper timing is often caused by a faulty timing chain/belt or issues with cam/crank sensors. It’s best to have timing corrected by a professional mechanic.

Addressing any engine issues or worn components that are making your car shake at idle will smooth out your engine’s performance for a more enjoyable, vibration-free ride.