does anyone run thier lsx swap with both front & rear o2 sensors? if this done, can you get a better tune? also, can you increase mpg/performance? thanks.

 

I'm sure some people do but the majority do not. You don't buy an LSX motor for smog legal fun. Lol I think you have a bit of a mixed interpretation. See rear 02 sensors are used to tell the PCM if the catalytic converters are working efficiently as an emissions solution. The PCM looks for a difference in signal between the front 02 to rear 02 sensor. The rear 02 sensor has nothing to do with the efficiency of the engine. This signal difference between front 02 sensor and rear 02 sensor lets the PCM know if the cats are operating efficiently. It has absolutely nothing to do with a (BETTER TUNE) or increase in (MPG/PERFORMANCE).