Pitcrew

Let me give you the short background, ls1 swapped nissan 240sx drift car, texa speed stage 3 cam, matching valvetrain, ported throttle body, headers and a cutom tune for everything from SPEED INC. in IL. Car wasn't running right, anything under 75% throttle and it ran super lean and popped and backfired a lil bit. Anything 75% throttle and more and it ran awesome, real good air/fuel and lots of go and power. Talked to speed inc, they said that only the front O2's were still in the pc and the back 2 got deleted, so they told me to disconnect the O2's which i did and the car was running freakin awesome, real good air/fuel and power everywhere. Whats up with that, they said that with the O2 disconnected that it will run on the base tune the loaded in there, but if the O2 were bad, shouldn't you be able to leave them connected and the car would just run a lil rich. ??????? any ideas would be awesome people cause we got an event this weekend we need to make.