The air filter element is blocked;

Throttle stuck;

Timing is not accurate;

Spark plug failure, high voltage coil failure;

Poor atomization of nozzle;

The valve is not tightly closed;

The cylinder is worn and the cylinder pressure is unreliable;

System feedback failure;

Too much refueling, large internal resistance of the engine, oil leakage and combustion;

Exhaust blockage;

Poor fuel quality;

……

It is recommended to send it to the factory for inspection and maintenance.