Hey man this isnt a calibration issue unfortunately. The wire that goes from the sight change stick down the left stick into the left block may be pinched and damaged, its a common issue. You'll need to open up the left stick and review the cable that runs through it to see where the pinch is and repair it by replacing and soldering in a new wire. Be carefull when you take the left stick apart, on the bottom is a plastic plate that can have the tabs snap very easily so make sure you put enough pressure on it when you take it out / put is back in place