Fake Subaru Catalytic Converters on Ebay / Amazon - non fouler spacer installed on the inside P0420

[@stvnswld]

Have you found a good alternative to the OEM cat? Everything I try throws the p0420. Tried a defouler to no avail. There has to be an aftermarket option that actually works without causing the code, right?

[@volks-jager]

the first thing you should do when getting a P0420 is replace both O2 sensors with new DENSOs, Only use Denso no other barnd works right, they are cheap on Amazon. i have found replacing the O2s get rid of the P0420 about half the time. if that doesnt work you need the cat. if the car is a PZEV nothing other that a factory OEM cat will work. on non-PZEV cars i have gooten the cheap cats from VEVOR to work