I know it can be fixed, but will it hurt/change anything for me to run/race my truck with no rear o2 sensors, and an "on" check engine light due to the lack of sensors? The exhaust is still stock; I just am using the bung for another sensor.

 

My friend has done it before in his mustang...no problem....

 

Why not just weld a extra bung in the exhaust. Any good exhaust shop should be able to do that for you.

 

I've done it many times w/ no issues. The 02 sensors aren't used at WOT.