I am new to the forum so a bit of history.

I have a 2011 G37xs Stillen supercharged. I purchased it this way from dealership surprisingly.

I started getting O2 error codes. Replaced 02 sensor on lower passenger side. This did not resolve. I installed an electric 02 eliminator. codes kind of cleared but they stay in the system as if drive cycle never finishes MIL light is not on anymore. been driven over a thousand miles.

Passenger side CAT does rattle when I take off at times. I'm thinking its really messed up.

So I ordered INVIDIA HFC's should get them by next Friday. I have stock catback exhaust. Does anyone think the new CATs will resolve issue and will I need a new Tune for after adding them. Like 700 bucks for the Tune so hope not...

 

It's best to get it tuned afterwards. First of all, you do not konw what kind of tune came with the car. Your A/F might be off and burning your cats alive. Who knows.

 

You could have made o2 sensor spacer by using old spark plug break the ceramic off and use the metal socket and screw o2 sensor onto it then screw onto cat

 

P0131? That was the code I pulled earlier in the summer. I don't have O2 sensors (using one of those ports for AFR) and the Uprev programming is supposed to ignore all of the O2 stuff so it was a mystery to me. Do you have an AFR gauge? you need to be able to monitor the air fuel ratio. Moving to HFCs should not require a retune. I know of others with the Stillen kit that moved to test pipes with no problem. What I found triggered the P0131 for me was pinched MAF wiring. The wire routing from the kit is not ideaL. After I replaced the frayed wiring and rerouted it I have had no problems

 

Thanks for the replys. So to update. I got Invidia HFC's put on at my local shop cost was about 150.00 to put on both. Car sounds a little bit louder kind of has a rumble to it at idle with the stock exhaust. So I checked codes with my code reader and got P0441 - EVAP PURGE FLOW/MON and P0430 - Cat system bank 2 and P0420 - Cat system bank 1. I cleared the codes and drove a little. The P0441 is gone but not sure if it will come back. Other 2 still there. I must have something going on with my mixture or a short. Just not sure.... Maybe need to take car to a shop to fix. Anyone know a good place that affordable to go in North Houston. Car does seem to drive ok but with slight lag. I do not have an AFR gauge unfortunately.