After buying my 2007 Cayman S in early June, I started getting a CEL which, after pulling the codes, ended up being a P2097 - Post Catalyst Fuel Trim System Too Rich Bank 1. The car has 120k miles, and my initial research pulled up that the post-cat O2 sensors were probably bad. I replaced both sensors just to be safe, and everything was fine for a while. In the last week or so, I've started getting the same CEL/code coming up again and now I'm concerned that it's something else. It doesn't sound like I have an exhaust leak anywhere, which is making me look at the cats possibly going bad. Is there any easy way for me to check that myself? Also, could it still be related to the O2 sensors in any way?