closed loop issues PLEASE HELP!!

I have an 01 cavalier ld9 with the gm speed density reflash for the supercharger kit. the car was tuned for my turbo and it was done in open loop, since then the ect vs. start up ect has been changed back to stock values and reflashed back onto the car. the problem im running into is the vehicle is stuck in open loop (verified on a snap on verdict scan tool) the car is throwing a p0130 and ive replaced the main upstream o2 sensor twice, checked the wiring to the pcm and it all checks out ok. Im not sure if its firmware related or the pcm is going bad but the car seems to idle like shit and will stall out when coming to a stop when the a/c is on. its running rather rich also and also causing it to throw a p0300 random misfire code and ive changed the plugs out also to good brand new plugs.