What should I do if Li Xia N3 idling is unstable?

For the question you asked, it may be that the throttle is stuck or beyond its adjustment range due to carbon deposition blocking the idle channel, or it may be that the throttle shaft or idle motor is stuck and cannot return due to too much carbon deposition, which leads to the increase of idle speed after receiving oil. In many cases, after cleaning the throttle, the idle speed of oil collection will increase. This is because when cleaning the carbon deposit, the carbon deposit solution enters the throttle shaft, causing the blockage between the throttle shaft and the valve body base. There is also the jitter problem when the speed is about 40 per hour. If this fault has nothing to do with whether the vehicle is accelerating or decelerating at that time, but only with the speed, then this fault is caused by the dynamic imbalance of the high-speed rotating parts with large mass. These parts include: tires, rims, half shafts, etc. When the vehicle is running, it will inevitably cause the deformation of these components, thus changing their dynamic balance. Even if there is no obvious deformation, it is enough to cause the vehicle to shake because of some silt foreign objects attached. So you should not only check the tires, but also check other parts that may cause high-speed jitter one by one. I hope my answer is helpful to you.