What causes engine shaking at idle?
3 Answers
The reasons for engine shaking at idle are as follows: 1. Fuel quality issues: The shaking may be caused by fuel quality problems, such as using gasoline with a lower octane rating than recommended or poor-quality gasoline, which can lead to idle shaking. If this problem occurs immediately after refueling, it is most likely due to fuel quality issues. In this case, it is necessary to go to a 4S shop for inspection and repair to see if the engine has been damaged. 2. Spark plug issues: Aging, damage, or malfunction of spark plugs can also cause idle shaking. For example, excessive carbon buildup on spark plugs can be resolved by replacing them with a new set, and the shaking problem will disappear.
The root cause of idle shaking is unstable combustion. Defects in the ignition system, such as excessive spark plug gap or weakened ignition coils, can cause misfires. Clogged fuel injectors in the fuel system lead to uneven mixture and pressure imbalance. Carbon deposits in the intake tract obstruct airflow, while exhaust pipe leaks or abnormal sensor feedback confuse the ECU's control. Damaged engine mounts fail to absorb vibrations, directly transmitting the shaking. I've personally tried simple troubleshooting methods like replacing spark plugs and cleaning carbon deposits, which solved most of the issue. However, this problem can increase fuel consumption by over 20% and even damage the catalytic converter, affecting exhaust emissions. It's recommended to first check voltage stability and then examine throttle position sensor data for more accurate professional diagnosis.
Shaking is a sign of unstable idling, often caused by worn spark plugs failing to ignite or clogged fuel injectors leading to uneven fuel supply. A dirty throttle body causing poor air intake can also result in shaking, while aging or damaged engine mount bushings will exacerbate vibrations. It is recommended to first clean the fuel system and replace old components. If left unrepaired, aside from increased fuel consumption, acceleration may become jerky, posing potential hazards. A friend of mine ignored this issue, resulting in cylinder scoring and repair costs amounting to thousands. It's crucial to promptly visit a repair shop for a computer diagnosis to check if the ignition timing is correct and adjust ECU parameters to ensure safe driving.
