Gas mileage low?

Hello,

Any time an engine is not performing as it is supposed to, like getting poor gas mileage, it can be due to a number of components being worn or defectives.

It can also have a faulty oxygen sensor and that can impact the air fuel ratio. Typically, a bad oxygen sensor will trigger the check engine light.
It will be a good idea to do a simple tune up to restore the performance and regain the fuel mileage.
A typical tune up will include changing out oil, spark plugs, air filter, fuel filter, clean out the throttle body, mass air flow sensor etc.

Here is a helpful guide on tune up:

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

I have attached diagrams for your reference.

Please let me know of any questions.
Thank you.