I have 2 02 sensors on my stock downpipe and the ZZP catless downpipe didnt have an option for another 02 bung down the pipe what do i do with the second o2 sensor?

 

You can just get another o2 bung welded in.or if you happen to find somebody with a shiney hiney header for sale,they have an o2 bung in them.I have the same header an had to plug it since I still have the stock downpipe

 

The downstream O2 sensor monitors catalytic converter efficiency. If your downpipe doesn't have a catalytic converter it won't matter if you plug in the 2nd O2 sensor or not, it will still set the check engine light.