What causes engine idle shaking and stalling?
2 Answers
There are two main reasons for engine idle shaking and stalling: 1. Dirty throttle body: This can cause the throttle valve to not close properly or the idle speed control motor to get stuck, both of which can lead to excessively high engine idle speed. 2. Worn engine mounts: Engine mounts serve as the vibration damping system for the engine. If there are issues with the engine mounts, it can cause shaking during idle.
Last summer, my car suddenly started shaking violently while idling at a traffic light, and then stalled completely after a while, which really startled me. I initially thought it was a minor issue, but later discovered it was mainly caused by excessive carbon buildup in the throttle body. The mechanic explained that carbon deposits can block the airflow passages, disrupting the air-fuel mixture ratio and causing delayed ignition, resulting in unstable idling or even stalling. Additionally, worn-out spark plugs are another common culprit, as electrode erosion affects ignition efficiency. If there are impurities in the fuel system and the fuel injectors don't atomize properly, the situation worsens. It's recommended to regularly clean the throttle body and fuel system. I personally use spray cleaners for DIY maintenance, which works quite well. Don’t ignore these issues—address them promptly to prevent minor problems from escalating into major failures, such as damaging the engine internals.
