What is the reason for high fuel consumption?

Insufficient air pressure, the vehicle has not been maintained for a long time.

1, insufficient air pressure. Insufficient air pressure will increase the contact area between the tire and the ground and increase the friction, that is, the driving resistance will increase and the fuel consumption will increase.

The vehicle has not been maintained for a long time. Dirty oil and air filters can also lead to increased fuel consumption. Dirty oil will lead to poor lubrication and increase the resistance of all moving parts of the engine. More energy is needed to overcome resistance and fuel consumption will increase.