My Wife’s RX350 - AWD- is coding P430 on and off. It comes on for no reason and off for no reason. When it comes on It stays for awhile then seems to clear itself. I have had it to carmax where we bought it (not covered under extended warranty). They said we need to replace the cat - which they are giving me at half price. I’m told they did check the exhaust for leaks and it doesn’t have one. I’m assuming they checked the electrical as well. We started with a P013c code which the o2 sensor - bank 2 - was replaced. It was shortly after this we started getting the P430. I am not entirely certain replacing the cat will solve the problem. I’m afraid of spending that money to replace it and it coming back. Looking for some advice on what to do. Also I’m not mechanic but I have done some things with cars so not afraid of getting my hands dirty.