So my 05 RL with 260k on it. I'm getting a p0420 and p0430 codes. A few months ago I had a p0420 code. So I changed all 4 02 sensors with ntk from rockauto. That didn't resolve the issue. So I ended up putting in new rv6 high flow cats. The codes went away for a few weeks and now it's back with p0420 and p0430. So I went ahead and ordered all 4 new 02 sensors again, ntk from rockauto, codes are still there. What else would cause these codes? The car runs fine at times but sometimes I do feel it hesitate and I gotta floor it to get it moving. Any thoughts?