Occasional P0430 / New O2 Sensors
 

A few months ago, I received a P0430 code. Cat efficiency below threshold bank 2.

I reset the code and drove for a few months with no problems. The code comes back and I reset it again. I drive for about a month and the code returns.

*Mind you, the permanent code does go away after the proper drive cycle.

Now, the code appears about once a week. I changed all 4 O2 sensors over the weekend, reset the codes, and the permanent code disappeared. About 30 miles later, the code reappears.

Is this characteristic of the driver side cat going bad? or bad fuel injectors? The spark plugs were changed about 50k miles ago (60k miles, I'm at 108k now.)...perhaps a plug change next? thoughts?

*I also tossed in some cat cleaner in the gas tank over the weekend. I might run the tank until empty and see if the code returns.

thanks!

Your post cat sensors are there to tell you whether your cat works properly or it doesn’t. If catalyst efficiency fault keeps coming back and you have no faults for upstream sensors or any other faults then your cat is on its way out. Just make sure you have no exhaust leaks.

If this code keeps reappearing than probability is high that your catalytic converters are clogged or damaged and need to be replaced. It’s a great chance to get HFC’s or test pipes. You will do more harm than good pouring catalytic converter cleaner in your gasoline tank. The only thing you should ever consider pouring into your gasoline tank is fuel injector cleaner like Chevron fuel injector cleaner etc. or fuel system cleaner. At 100K+ miles for preventative maintenance I would definitely replace your spark plugs make sure to use the Nissan OEM Denso spark plugs they work well in our cars. Also I would check your coils too.