I planed a flight from Orlando to Miami. I was in the default 737-800. Shortly after take off at about 2,000 ft I saw the aircraft moving around the yaw access like there was a cross wind. But there was no wind. I looked out side and saw the rudder moving left and right but I was doing nothing with the rudder. It was like someone was controlling my rudder. All the other controls were just fine. The next thing I did was to calibrate my joystick but that didn't help one bit. I even reset my failures section in hope of fixing it but that didn't do anything either. This might be some info that may help (I have a thrust master joystick and no rudder peddles the is a center to the controls).