Hello everyone, first post here and I'm struggling with deciding what to do/what is going on. I'll try my best to explain it. I took my 09' G37x to the Infiniti dealership with a CEL code that was coming on and off for about a month. On cold start, the engine sounded & felt great but the idle was higher than usual. After warming up the engine and driving around for errands, I would try and start it again it would misfire and shake the car a bit. The dealership did a smoke test and found that there were holes in my catalytic converter, the CEL code was P0420 and said the car is running lean. Again tonight I drove it to a friends house and the CEL was blinking and car was misfiring again. I guess my question is that would these holes really cause my engine to misfire/stall? If I were to get new Catalytic Converters should I go with HFC's? I am starting a new job soon and would really like to get this problem solved. I've searched the forums and asked all my buddies about it, to no avail. If I were to replace the cats should I get new O2 sensors as well? When I reset the code, it'll come back on in 30 minutes, so they're reading the O2 correctly, right? I appreciate any insight and recommendations, I've been on these forums a lot and they've helped me immensely so I am hoping you guys can solve this. Thank you so much and let me know if I can provide anymore details/symptoms.

 

Replace the cats. I did Z1 hfc and while they fit great I wouldn't recommend them. The cat is so small (100 cell) it might as well not be there. My garage smells like gasoline because it does such a poor job at emissions. They might as well be test pipes. And analogous to test pipes, the rasp is borderline embarrassing.

 

If there is big blockage in exhaust engine will misfire. When exhaust gases going back to combustion chamber due to blockage there will be misfires.

 

Well they did a smoke test and found there were holes, if it was blocked they should've said something? But on the otherhand the dealerships are really just looking for money, and not customer satisfaction sounds like I'll be replacing the cats regardless

 

I am not sure how they did smoke test on exhaust, i did couple times on intake manifold, but exhaust?
Here is sample pic for you of failed magnaflow cat.

 

Just Installed Fast Intention RHFC. Quite pleased. No smell. No CEL. Slight increase in deep tone with normal driving and a moderate increase in deep tone when you get on it. They are coupled with only Tanabe Medalion Mufflers.
Good Luck!

 

Hi there. New member, first post. No CEL yet. My driver side cat is rattling like a MF for a couple of months. Car is a 2010 g37xs sedan with 87k. I went to the dealer they said bank 2 driver side is bad, and recommend replacement of both of course , and as I thought no dice on the emissions warranty. They quoted me a stupid price of $3,100!! I was looking at FI RHFC with stock exhaust. Can’t afford cats and exhaust. Money is tight and looking to just replace with OEM. There is a member selling OEM cats off his Q60s, and was wondering if they would work on my 2010 G37xS? Any feedback would me much appreciated.

 

How much would a used swap cost??