What are the reasons for a car's lack of power in second gear?

[AaronLynn]

The reason for a car's lack of power in second gear may be due to abnormal fuel injection system or mismatched gear and speed. Speed range: First gear corresponds to a speed of 0-5km/h. Second gear corresponds to a speed of 5-20km/h, third gear corresponds to 20-40km/h, fourth gear corresponds to 40-60km/h, and fifth gear corresponds to 60-100km/h. Shifting timing: For most cars, the optimal shifting timing is when the engine reaches 2000r/min, and should not exceed 2500r/min. For some high-displacement, high-power engines, shifting can be done around 3000r/min.