After you answered me I got a new code p0430. now I have p0420 and p0430. if I go to permanent codes I get p0420, but on stored codes I get p0420 and p0430. the check engine light sometimes can go off by its self, but the code is still stored, and comes back a few days later. can it be both catalytic converters are out, or can it be something else. replacing one catalytic converter is expensive and two is just too much. there are no other codes coming up except these two. and some times only p0420 is stored sometimes p0430 is stored, and sometimes both stored, but p0420 is the one that always shows up on permanent codes. I am not sure if every scanner divides them, but mine has permanent and stored codes. this is weird, but its happening.
those are known for bad cats, but I would change the front cat first as that's more often the one that goes out and just pray the back one hasn't gone bad too