Hello all! I have a 2021 wrx with 20k miles.
I got cel P0420
AFR is at 14.7 while driving.
I have a Grimspeed v2 gesi catted j pipe, remark catback as well. I’ve had Jpipe installed for about 3 months and exhaust for a year or so. Car is pro tuned at the moment. Any idea what it could be before...