Hi, I am new to this so please bear with me. I purchased a used Prusa i3 Mk3s+ with MMU3. It went through calibration without challenges however when I print it fails after a few layers, the printers carries on as if it is printing however there is no extrusion. I saw a post that recommended trying printing with extraction off. I did this and the prints do now finish however as you can imagine they look like they are covered in spiders webs. Slicer setting when it fails are set to .8mm. Hotend appears to be Revo.

I have cleaned the gears on the hotend however the problem persists. Any thoughts on how to correct this?