I had this problem, with mine, or at least one of my axis was completely messed up. I took off the baseplate of the joystick (4 screws) and followed the wires from that axis to the board. I disconnected the wires from the board (just a small plastic clip, 3 wires in it if my memory serves me right), cleaned it lightly, and reconnected it. Problem was solved. It's worth a shot to take a look.