To loosen the O2 I just use an O2 socket and a ratchet and maybe a little pb if it needs it. As far as the PCM goes, most places will flash your VIN into it before they ship it out, I see them go for 30-50 bucks all the time. Since the dumbass who fiddled with the tune set the shift points at 5K, who knows what else the messed with.....could even be why you keep trashing transmissions and at this point you might as well get a whole new trans since the one you have seems plagued.