Why is Gas mileage low?

What are the codes? Have you done the basics such as new plugs, wires and filters?

there are no codes showing since the sensor replaced. Mechanic is not picking up anything specific. He has done all basic care and, as a subaru specialist, has never seen such low gas mileage. He had me use fuel injector cleaner and no difference. I am 3rd owner, has 118,000 miles and have all records of maintenance since 2007.

Did that and gets nothing that indicates any issue. He says after 32 years working on subarus ' he has never run into this. He even reached out to another guy who works in Subaru in Fairbanks and he also has never seen has mileage this low with no indicators as why. This is a last desperate hope that someone has a solution

Is it running too cold? If it never gets out of the startup rich phase your mileage would suffer.

No. I had an issue with cold starts last winter and he fixed that and checked out all mixture ratios, and components involved in the running, driving, starting and zilch

OK. How about the obvious that has not been mentioned? A leak or someone stealing your gas? If this is a computer generated fuel economy number the computer could be wrong. Check the mileage the old fashioned way.

Thank you. Have had cap lock and I did do it the old fashioned way lol, been driving for over 50 years before all this computerized junk. No leak, no smell of has no drops or wet areas. I have appreciated all the suggestions you have put forward.

Thank you all for your help. God bless and stay safe

Does the engine oil smell like gas?

No. There is no smell of has anywhere. Also checked out exhaust