sadly, it's an 03 with nearly 140k miles (and up till now, no real problems!)

Thanks, guess there's no easy way around this. Has anyone cleared a CEL by cleaning the fuel system?

Sorry for the noob questions- Went to Autozone and got printout for CEL. I've seen a lot of p0420 posts on here, but looking for clarification. Is there a way to know for sure if the problem is O2 sensor (and if so, which one?) or the CC? Does anyone know the approx cost of replacing the CC? Any goo...