Why does the car body shake violently when the AC is turned on?

[ColinLee]

The reason for the violent shaking of the car body when the AC is turned on is the increased load on the engine. The following are specific explanations: 1. The power output of each cylinder of the engine is uneven, and the variation between cycles of the same cylinder is relatively large: The lower the engine speed, the greater the variation. When the AC button is pressed, the vehicle's speed will increase. Observe whether the increase in speed is the same as before. If not, the throttle body needs to be checked. 2. If the increase in engine speed is consistent, the spark plugs and fuel injectors need to be inspected: Irregular variations in spark energy and fuel injection quantity cause variations between different cylinders and cycles of the same cylinder. It is necessary to check the burning condition of the spark plugs, whether the gaps are consistent, and the consistency of fuel injector flow, especially the consistency at low flow rates.