Well, this might be good question to stump ya guys, hope you can help. My car was bought used, and came with a basssini x pipe with cats. Ok, it only has (2) 02 sensors being used, which are Blue, Now I was told that they are the end readers not the Green one which should be in there. I'm really comfused about this. I don't get a check engine light, and the car does run really rich, toward lowend and high end. I can't even see were the others 02 were, they must have a MIL eliminators on it right?, so it wont blow a check engine light? If ya have any info on this let me know thanks guys? :??: