Update, it is indeed behind the driver's side tire for anyone needing this info.
Car problems always persist and only get worse... if in Calizuela, warranty is70000 mi.Around 60,000. I'v contacted Subaru and the Federal Extension covers ECM and Cats.
If the problem persist, I will see if maybe they can look at the cat, thanks for insight though!
I should have mentioned, I replaced the rear o2 sensor (so far so good). If the problem persists even after replacing the o2 I'll hit up Subie Service.Car problems always persist and only get worse... if in Calizuela, warranty is70000 mi.