X Trail Fuel Consumption

Well, get your printer ready:

Tires, Tire pressure, fuel filter, fuel pump, fuel injectors, air filter, cleanliness of the throttle body and intake manifold, wrong octane, and many many other factors can contribute to this.

Check your tread depths and tire pressure, replace the air filter, replace the fuel filter, run some injector cleaner in the tank, pop off your intake pipe at the throttle body and spray some throttle body cleaner in there, and lastly listen to the rear of the car by the gastank while the car is running. If you hear a hum or a whilste sound, noticabley, then your fuel pump may be having problems. It is recommended to replace the fuel pump every two to three years depending on mileage.

That should give you a good place to start.