CEL P0430 code

Hi Taco world,

I have a 2006 4x4 Taco w 118,000 miles. CEL came on and had it scanned and it threw a P0430. Given the mileage and age of the vehicle, I decided to replace the downstream O2 sensor since it was the original and probably needed regardless. Used a Denso, but had to wire it myself to the existing wire clip. Installed it and disconnected the neg terminal to clear the CEL. CEL came back on 2 days later. I drove for another day and CEL turns off on its own. Another day, and it's back on. Day 6 after replacement its back off again and has stayed off for last 2 days.

Any suggestions or commentary on what the cause is of the CEL warnings are, and how to stop them if they continue?

Thanks.

 

I believe that a po430 is catalytic converter effientcy code below threshold, meaning it could need a converter.

 

Yeah, I'm aware of that paradise, but I've also read a lot about this issue and seen everything from bad O2 sensor, to faulty/cracked air intake to bad AF sensor etc, and only sometimes is it the CAT.

My truck doesn't exhibit any symptoms other than poor mpg(12 mpg city) and considering the miles on it presently, I decided to replace the O2 sensor to start.

I guess my next step if the CEL keeps appearing is to remove the exhaust and look inside the CAT to see if it still looks in tact.