What are the causes of idle shaking in a new car?

[LeRuby]

New car idle shaking may be caused by the following reasons: 1. Engine carbon deposits: Excessive carbon deposits inside the engine can cause idle shaking after a cold start. Due to excessive carbon deposits, a large amount of gas sprayed by the engine will be absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture, which makes starting difficult and causes shaking. 2. Ignition system issues: Poor performance of the ignition system or suboptimal spark plug firing can lead to idle shaking in a new car. 3. Unstable fuel pressure: Abnormal fuel pump supply pressure or incorrect readings and poor performance of the intake pressure sensor can cause body shaking. It is recommended to check the fuel supply pressure and intake pressure sensor at a 4S shop to ensure they are functioning properly.

[CalvinRose]

My newly bought car shakes badly when stopping at a red light, and the inspection found that it might be due to improperly installed or dirty spark plugs. A new car should run smoothly, but slight shaking during the break-in period is normal; however, if it's severe, it could indicate a clogged fuel system or carbon buildup in the throttle. I also suspect loose engine mounts—if they weren't properly secured during factory assembly, this could happen. Idle shaking makes the ride uncomfortable and raises concerns about engine longevity. It's recommended to return to the 4S shop for diagnostics as soon as possible—don't delay. They can use diagnostic tools to check if it's an ECU calibration issue. New cars come with a warranty, so repairs are usually free. Additionally, driving habits like sudden stops and starts can worsen the shaking, so smooth driving is crucial.

[OCalvin]

Idle shaking is often caused by an imbalance in engine cylinder operation, such as a misfire in one cylinder. Faulty spark plugs or ignition coils are key culprits, and even new cars may have improper installation. If the fuel injectors in the fuel injection system are clogged, uneven fuel supply can lead to shaking. A dirty mass airflow sensor can disrupt the air-fuel ratio, and improper ECU adjustments may cause engine surging. I often help friends diagnose car issues and recommend checking these components; new cars typically use diagnostic tools to read trouble codes for problem identification. Additionally, temperature changes affect idle speed, especially noticeable during cold starts. If accompanied by unusual noises or increased fuel consumption, prompt troubleshooting is advised to prevent internal engine damage. Regular maintenance, such as throttle body cleaning, can prevent issues, but avoid disassembling new cars yourself.

[LaTanner]

I noticed a slight shaking when the new car is idling, which might be normal especially during the break-in period within the first 1,000 kilometers. The engine needs time to adapt, but persistent shaking should be taken seriously. Possible causes include a dirty air filter or poor fuel quality, as using low-quality fuel can easily clog the system. Loose connections in the ignition circuit might also cause vibrations. I usually pay attention to these during maintenance and change the oil regularly to keep it clean. If the shaking worsens, it's advisable not to wait and to quickly check if the engine mounts or shock absorbers are damaged. Idling vibrations reduce driving comfort and increase wear, affecting long-term durability. Developing good habits, such as reducing idle time, can help alleviate the issue. Early detection and resolution save both peace of mind and money.