Hi,
I tried pretty much everything you said and have come to a conclusion that the problem is with my filament feeding motor. I completely take out all the filament, then manually insert it while moving the motor thru the maintenance menu, and the filament just gets dented, with heavy markings of the motor and not get pushed up. I completely loosened it too, and it still does it.
I think I should replace the motor. Can somebody send me a link to one, should I get a UM2 one or a UM2+ one? (I have a UM2 but if the UM2+ one is compatible I would rather pay extra for a slight upgrade (+ version) if it is compatible and won't cause problems.
UPDATE: Today I cleaned out the motor and now I think the problem is not with the motor, but is with the extruder. When I manually pull the filament up to the extruder it moves the filament up fine, but the second some filament comes out the extruder, it is not able to push the filament up as well. Why could this be???