snup

Hey, a few months ago i bought a 2004 350z imported from Germany to Finland, and i've been getting a check-engine light on for some time now, the fault code it displays is " P0430 ", at one point it also gave me the codes " P0158 " and " P0138 ".
As i have understood, the P0430 has to do with the catalytic converter which may be a bit clogged, i've been trying to drive the car more aggressively with high octane gas, but it doesnt seem to have an effect since the fault code keeps coming back.
The P0158 and P0138 keep popping up from time to time, but not as often as the catalytic converter one, a friend of mine read the fault codes with some kind of reader that gives a wider variety of information than the one i have, i attached some pictures of what it showed.
Would ya'll recommend me to replace the O2 sensors or any tips on how i should proceed?
I am also not sure if the catalytic converter has been emptied or not, is there a way i could check it, and would it have an effect on something the fault codes would be implying? It has been straight piped, but other than that, i don't know if something else has been done to the exhaust system prior to my ownership.
The O2 voltages or values remain the same even if the engine is running or not, doesn't have an effect if i press the gas pedal or just running idle.

If it has any significance, the car has roughly 124k miles (just under 200 000km), i've driven it for about 2k miles.
I'm also new to the car and 350z scene so please go easy on me

Ponyryd

Welcome. You have a cat efficiency code, as well as some 02 sensor codes, could be an 02 sensor, or could be a fuel injector/fuel delivery issue as well. The easiest thing to try if you don’t trust a shop to diagnose it for you is a new sensor, but since it’s both banks, it’s most likely a fuel delivery issue, which could cause all these faults. Best to take it to a pro unless you want to get deep into it checking injectors and vacuum leaks.
As far as the cat code it’s only one bank giving you the fault it’s most likely a failed catalytic converter. If you can get a pic of them we could tell you if they’re stock or not, many people change them out for more power and sound, and I actually have a set on order right now to replace my stock ones.
Driving hard won’t do anything to fix the issue, and there’s no easy way to tell if they’re been punched out or not, aside from taking out an 02 sensor and sticking a boroscope, or maybe a dipstick up or down the tube to check. If you’re only really concerned about the light, and not the converter itself, you could try 02 anti-foulers, they sometimes work for that code.

PeterPotatoes

I'm a mechanic but since my Z has yet to have problems, I'm not familiar with their common issues. So this is what I would do to diag something unfamiliar.

You're running rich, on both banks. Fist check everything and do the cheap stuff first. Get under the car and check your wiring, maybe the harness was extended or rubbing itself bear. See if the cats are stock or not.

Check your intakes, if the filters are clogged with dirt they could make you run rich, for all you know the pcv check valve is stuck open and sucking too much oil through coating the inside of your filter. Get a maf cleaner and spray down the sensor, could be dirty.

If you can get your hands on a good scan tool you can watch your bank 2 sensors efficiency. Bank one should go rich to lean looking like a AC wave, bank two should be a lot straighter. If you know someone with a osiliscope, you can check straight from the harness. The car needs to be warmed up fully in closed loop.

For all you know the guy before you changed the fuel pump to a AEM 340l one or was tuning the car and programed it to run rich.

The cat code I'd worry about after you fix the rich running issue. One seems to be working fine but maybe you were sucking oil through the intake, both would end up needing to be changed since the other would soon follow.

G/L

icer5160

iTrader: (4)

Running rich or sucking in oil from a faulty PCV valve can cause premature failure of CATs. As others have said, resolve the rich condition issue 1st before diagnosing the CATs/O2 sensors. Also, if you believe Scotty Kilmer's mechanic tricks, *sometimes* dumping kerosene into your gas tank can help clean up clogged CATs and clear CAT efficiency codes. Not something I have personally tried/done, but I have used BG-44K (fuel system cleaner) in my Z at regular intervals and I have to say, it smells/looks like kerosene. Also, I've never had any ignition system or fuel delivery issues yet (fingers crossed).
Good Luck!
-Icer