I have a relatively new Ender 3 Pro, stock except for adding a tempered glass bed. I've fed about 3 kg of PLA filament so far, all Solutech brand. Near the end of the last reel, I started hearing a chunk noise. It varies in rate, between several/minute to going 10-15 between chunks. This has continued into a brand new, just unsealed reel so I don't think it's associated with the filament.
I was able to finally discover that the sound is coming from the extruder stepper area and was able to see that when this happens, the filament drive wheel snaps back maybe 30-40 degrees. (This happens in the middle of printing a line, not when the filament retracts between lines.) I'm assuming that the stepper motor is slipping. There is no sign of gaps in the printed model nor is the filament on the reel binding that I can see.
I'm guessing maybe that the filament is being fed faster than the hot end can accept it, causing back pressure.
I'm using Cura 4.4.0 as my slicer the whole time and while I have changed some settings, everything associated with speed, feed rate, hot end temperature and such are all stock. I did not notice this happening until recently.
Has anyone seen this happen before? Anyone have any idea what could be causing this?