Help!! Emission/O2 Sensor

[Joey41]

So I am getting the code PO420, which is catalyst efficiency low-bank 1. So of course this was scanned at Autozone and the guy told me I needed to replace the O2 sensor up top on the drivers side. Well the connector on the sensor they sold me was not correct and I could not find the correct one except for the dealer-$140. The guy at the dealer then told me to try RXP decarbonizer first, which I am currently. My question is if the RXP does not work, what should I do. My EGR & Cat were replaced about two years ago, and I have never replaced my o2's, i know that's bad. It's a 97 Camaro, 222,000 miles, and I hate to sound cheap, but I am broke so I'm trying to go the least expensive route possible. There may be a slight, slight exhaust leak where the EGR tube goes into the exhaust manifold, but I am not positive. Only guessing, because that screw hole was stripped years ago. Any suggestions are greatly appreciated. I was thinking I would try replacing both o2's on bank 1 (the drivers side & pre-cat). Let me know what you guys think, I'm trying to pass inspection. Thanks!

[Joey41]

Re: Help!! Emission/O2 Sensor

So nobody replied at all, maybe because I didn't post in the emission section. I had already looked at what was there... anyhow. For anyone that this may help, it was the cat. Had it replaced this morning and passed inspection an hour later after resetting the code and driving 50 miles to get the computer back to normal.

I never thought that it would go only being two years old, but apparently it is not that odd from what my exhaust guy told me. Now more than likely I do have some other engine issue that is causing it to go out, but for now at least I'm legal!