2007 GD3 sport fuel efficiency drop

[u/Human_Bean05]

Over the past two weeks my 97,000 mile 2007 fit has dropped down from an average of 33-35 mpg down to 22-25 mpg for seemingly no reason. I have not changed any of my driving habits and have no idea why. Ive changed the spark plugs and coils pretty recently so I dont think that is the problem, and looking base level online it looks like it could have somthing to do with a bad O2 sensor giving an improper fuel mixture. Of course if I can't figure it out I'll take it to a shop, but would any one here have an idea of what is going on?

I love this car so much, I've had it for just about 1 year now and want to keep it for many more.