The causes of engine underpower are:

1, carbon: including cylinder carbon, throttle carbon, spark plug carbon, carbon intake carbon and so on too much carbon when the ignition energy of the car is reduced, intake efficiency is reduced;

2, piston, piston ring: serious wear of the cylinder caused by the piston, piston ring and cylinder clearance increase, poor sealing, resulting in cylinder head leakage, the cylinder compression pressure is reduced;

3. Air intake: air is one of the power sources of the engine. If the air filter is used for a long time and is not cleaned in time, the lack of air will cause the combustible mixture to be too thick, which reduces the engine power.

4, engine overheating: insufficient engine oil, insufficient engine coolant, engine cooling device failure will increase the load of the engine, so that the engine heat dissipation is poor.