So, this all started immediately after I took off my SLP loudmouth catback because of the annoying RASP. Car still remains with a Open Y pipe. Car threw leans codes on both banks and wants to die out at Low RPMs, actually died on me twice making a right hand turn slowly and putting into reverse backing into a spot. Does this sound like a fuel pump to yall or maybe something to do with the open Y pipe? Vacuum leak?

An slp catback and an open y pipe are not very different as they both are wide open. I would look at your o2 sensors and the wiring as maybe you damaged wires while doing exhaust work. If the o2 sensors work then see what the readings are. Also look at your fuse for the sensors.