How to Calibrate the Extruder

It could also be the PTFE lining in the Throat is deformed cause the filament not to be extruded. and the Stepper is clicking because the filament will not extrude.
I have replaced several throats because the lining deformed pushing into the nozzle, as shown in the photo.

Throat on left, Nozzle on right they are sitting inside my spare lead-screw nuts.
Nozzle & Throat.jpg

The PTFE lining pushed into the nozzle partially plugging it, and the PFTE lining was compress against the throat making the bottom of the PTFE lining 2.25mm.
Pressing the excess PTFE into the Nozzle making a insulating barrier that would not allow the filament to melt correctly.

Other times the lining just deformed causing the filament to get stuck inside the throat. Picture shows the worse case I have experienced.