If your Airwolf printer is no longer extruding correctly there is potential the head could be clogged.  This is indicated by uneven filament flow that contains bubbles and black debris in the plastic.  It can also be indicated by a complete lack of filament flow.  Incorrect filament switching can also cause this as materials heat to different temperatures.  Airwolf provides a guide that demonstrates how to clean the nozzle on your 3D printer.

Guide: https://airwolf3d.freshdesk.com/support/solutions/articles/5000662375-axiom-hot-end-nozzle-cleaning