From all diagnosis, it appears I need driver's side cat replaced. P0430 . No leaks. Lexus Service Mgr is 99% sure. My mechanic is 95% sure.

What would you do to make this repair? I live in a state that doesn't do emission testing.

This is a long term keeper with no plans on ever selling.

 

I would replace the cat if I planned on keeping the car long term. I would double check to see if you have an exhaust leak around the Y pipe though, I believe that's a common reason for P0430.

 

She checked the Y pipe. Thanks!