So I've had a P0430 code come on my 2006 Nissan Pathfinder LE 17 times now. I've tried the cataclean stuff from Autozone and that removed the code for a while but it has come back. Finally I just gave in and took it to my local Nissan dealership who told I needed to replace the front driver side Cat and air fuel sensor. He showed me the Cat and it did not look clogged at all but the tech told me that even though its not clogged he has seen some that just stop working for no apparent reason. I question if it might just be the air fuel sensor that needs replacing. They quoted me 1200 to do the job.

The only performance difference I've seen in the pathfinder is that sometimes the rpm needle to jump a little as im coming to a stop or if I'm driving at a steady 40 mph the rpm need will almost seem a little confused as to what rmp it should be at so it roughly move. Not sure if that explains it accurately enough. They said my tranny looks good so they only other thing I could attribute it too is the cat or sensor, although the tech said the cat and sesnsor is just an emissions thing.

Anyways, I'm desperate and just want a straight answer as to what I should do and if any of who have experienced these issues.

Thanks!

You likely need a catalytic converter. The catalyst substrate can become inefficient in breaking down the exhaust gases, which will trigger the P0420 or P0430 DTC, depending on what bank the converter is on. There is no way to visually tell if a catalytic converter is inefficient by looking at it. You need to compare the readings of the front and rear oxygen sensors on that particular bank using a scan tool; the rich/lean cycling frequency will compared by the ECM in order to tell if the converter is efficient or not. The frequency of the rear oxygen sensor should be about half of that of the front's under testing conditions. An inefficient converter will not affect engine performance, unlike a restrictive or clogged converter.

I need some advice. I have a 2005 Pathfinder with about 185,000 miles. I have the P0430 code, but I do not think it is my cat. My reasoning is based on my O2 sensor readings. If I am correct, sensor 1 is before the first cat and sensor 2 is after. With the car engine off or at idle, sensors 1 and 2 on bank 1 both read 0.3 V. On bank 2, sensor 2 also reads 0.3 V, but sensor 1 reads 0.6 V. Similarly, as I drive the vehicle, sensor 1 on bank 2 always reads much higher than all the other sensors (and it is the only sensor that exceeds a reading of 1V). The post cat sensors on both banks always have similar numbers. Am I correct to assume my pre-cat sensor is faulty?