alright so here it goes..im new to using forums and im sick of people who have never owned a grand prix or anything with a 3.8l sc. because half of the time there wrong with there assumtions. so my check engine light was on and i went and got the codes read. it came back as a bad o2 sensor. to make a long story short. i unplugged the front o2 and disconnected the battery. got about 15 mins into this and realized i didnt know which o2 was bad...so i plugged the o2 back in and connected my battery..get the car started and theres this terrible knock..and i mean real terrible..it sounds and feels like the supercharger is the problem...also i pulled the belt off the supercharger after all of this just to spin the pulley and there is about a 1/2 inch play before you actually feel the supercharger grab...someone please help me out this is driving me nuts...