Why is it smooth when idling, and the engine will appear intermittent jitter after the air conditioner is started?

The most common thing is that dirty throttle or faulty throttle will lead to idle jitter. The main reason of dirty throttle is that there is carbon deposit at the joint between throttle valve plate shaft and throttle body, which leads to inaccurate throttle opening, so idling jitter will occur. So we can clean the throttle first. If it doesn't shake after cleaning, it means the throttle is dirty. If it still shakes after cleaning, it may be that the throttle assembly is damaged and the throttle needs to be replaced. Just a reminder, because all vehicles use electronic throttle now, you need to learn idle again after cleaning the throttle.