20 16 Zhizun, turn on the air conditioner at idle speed, the tachometer jumps up and down badly, and the idle speed is very unstable.

Usually when the air conditioner is turned on, it will shake. It's normal to say that shaking is not big. If the jitter is obvious, there is a problem. When the air conditioner is turned on, the engine load is large, and the large jitter indicates that the power is insufficient. Generally, first check whether the spark plug gap is too large, and if it is too large, it needs to be replaced. Remove the air filter tube to see if the throttle valve is too dirty.