i had some severe issues with my ender 3 pro 3d printer.
the problem was, that the filament didn´t want to come out of the nozzle. the temperarure was on 200 degrees, but almost nothing came out. i checked it double, but everything was fine, there was no error on the display.
the tubing for the filament wasn´t the best anymore, so i thought it would be best, to cut off a little bit of it. but again no filament.
the metal gear for the transport was fine too, only some small abrasive areas on it. to minimize the source of errors, i mounted the gear a little bit higher to get a perfect filament transport to the nozzle.
but again no success.
at the end i found, that the nozzle didn´t get enough temperature and the filament couldn´t get out of it. the motor couldn´t transport it and the gear wasn´t strong enough too.
two completely new extruder kits with a new tubing were ordered, because my second printer had the same issues some days ago.
after having replaced the complete unit, everything went fine again.
the printing can go on!