Check the engine water temperature sensor! It should be about the water temperature sensor. The engine has two water temperature sensors. One is for the instrument and the other is for the computer. The one for the instrument tells you the current water temperature display, and the one for the computer tells the computer the current temperature of the car engine. When the water temperature is given to the computer, After the sensor is broken, the computer will not receive the signal, which will cause the computer to adjust the mixture according to the usual mixture concentration during cold start, which will cause unstable idling