Is it possible that the two cats before the muffler are resonators? These don't have o2 sensors like the pre cats. I have a TRD factory exhaust that says its supposed to be cat back, and am thinking that if these are resonators, port may have thought they were cats when they installed TRD exhaust.

 

I doubt it. Sounds like Cali-spec exhaust to me.

 

The underhood emission sticker only says 2 TWC, and 2OS. yet, they are welded & look like cats

 

any pics ?

 

They're TWC's, described and illustrated in the .pdf in this thread:

https://www.yotatech.com/forums/f135/new-fj-cruiser-tech-manual-pdf-80936/

 

They cannot be TWC's as described, becasue three way cats require O2 sensors, which these clearly don't have.

 

what about this y-pipe setup

http://www.urdusa.com/product_info.p...5b45d0e15bef7d