HELP air/fuel ratio one bank rich one lean

[IXRsupercharged]

Hey. I have a supercharged 2000 mustang gt and the left bank is rich and right is lean. I pulled the plugs and the left plugs are black and the right are white. I have a AFM PMS and if I add more fuel it just makes the left bank even more rich and the right bank gets a little better but still lean. How can I even them out. Thanks