P0430 codes and dash lights on my 06. I have been reading and people say it is either the cats or the o2 sensor.
I am going to replace the o2 sensors first.
If it doesn't work.
Can I replace just the cats by welding in new after market ones?

 

Yes, an aftermarket catalytic converter will work, if that is what you need. Check Summit or Jegs for pricing.

Here is a good video on troubleshooting a P0420/P0430 code, despite the fact he's working on a Honda.

 

Do NOT blindly replace O2 sensors or a converter.

Do your diagnostics so you can actually determine the underlying reason for the fault code.

The video that redford pointed to describes the testing pretty well. You need to observe the O2 switching to see what the PCM is seeing, then you can determine what the fault actually is.

 

Thanks guys when it warms up around here I am going to get to work