Good morning all,
Have had my 2015 RCF for about 4 months now (and absolutely loving it!) and I'm at ~77k miles. I've had somewhat of a weird issue however. Every couple of weeks I'll get a check engine light with code P0430 for catalyst efficiency. It does not throw P0420 for the other bank. Here are the important points:
- It almost always only happens after running through the first 1/4 of the tank after a fill up.
- Rotten egg/sulfuric smell when getting on the gas/close to redline on the highway.
- It ALWAYS goes away on its own (no resetting/unplugging battery) before I even reach half a tank.
- The car drives and feels exactly the same. Only downside is that in normal mode, the passive "Eco" mode won't work because of what I assume is a blanket safety measure if a CEL is present. I don't hear any abnormal exhaust leak type sounds from the manifold area, but I also have a muffler delete so it may be hard to hear over that.

I'm having trouble believing it could really be my cats at 77k miles, but what else could it be? From the reading I've done, a catalyst efficiency code wouldn't be caused by faulty O2 sensors (quite the opposite? It takes good O2 sensors to monitor efficiency) but please correct me if I'm wrong. Could this be caused by sub optimal gasoline? I fill up with only 93, but it is the cheapest gas station in town by quite a bit.. if that matters?

 

Your catalytic converter is most likely going bad. You might need to get that checked. Did your RCF come with an aftermarket exhaust? The O2 sensor might have been damaged during installation as it is a bit tricky to unplug and then re-plug.