[Chrysler kid]

If the code is p0420 simply run a post cat oxygen sensor spacer. The p0420 is the rear oxygen sensor detecting either too much air flow or too little air flow

Considering you would want to superheat your exhaust to run leaner, you can safely assume at your mileage that since you are not suffering from loss of power, that the catalytic converter material has broken internally.

So get on amazon and run the low profile oxygen sensor spacer to eliminate the code.