Thats really odd... calibrating it should allow it to work out the min, max and centre points for your axises...
As the Z-axis is the 'grip-twist' for rudder, when it is centred, the red line should sit about halfway up the scale... when fully twisted tp one side (eg. left) it should drop to the bottom and when fully twisted the other way it should raise to the top (or vice versa... I cant remember offhand which way it actually goes)...
so try what brownbox has suggested... only when you unplug it, let it sit for a while as I remember reading about issues with the precision 2 having a metal base and building up a static charge that does weird things to it...
Once you plug it back in and run through the calibration routine, if the joystick is centred, and the redline is all the way at the bottom like that... then I think it might be stuffed...
