Fuel consumption problem?

Hello,

First thing you need to do is a engine tune up.
A tune up can restore engine performance.

A basic tune will include typical maintenance items.
Start with an oil change (if its due), change the spark plugs, change air filter, change fuel filter. Clean mass air flow sensor, clear idle air control valve.
Also might want to have a look at the owners manual and see what factory recommended maintenance is due (give your current mileage).

Here is a helpful guide on tune ups:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

I have attached the diagrams for your reference.

Please let me know of any questions.

Thank you.