First let me start by saying that I did search around when I first had this issue and thanks to you guys I was able to fix this about 2 months ago. I replaced both cats with Eastern Catalytic I had a custom muffler shop replace my y pipe with a custom piping they did to fix my exhaust leak. On top of that I replaced my o2 sensor when I first got this problem. I passed Illinois emissions with flying colors. I got the CEL this morning and checked the resistance on both o2 sensors and they seemed to be ok. As mentioned I replaced this o2 sensor. What else can this be? I am frustrated. Thanks in advance!!!!!

 

According to the manual, P0430 -Catalyst system efficiency below threshold.(bank 2)
- Gas leak on exhaust system
- Heated oxygen sensor
- Three way cat converter.

you stated you changed O2 sensor. Did you go with denso and the right part?

 

Yes. It's the factory o2 sensor.