Yah ive checked and cleaned it several times and we even had another motor and switched it out still the same I don't like these MK6 heads because the old ones you could adjust the plunger (tension on the filament) Im curious whether I can downgrade to one but anyways are you sure you couldn't feed through from a clog or were you feeding the filament in and it was hitting that nut right before the heatblock? I ask that cause I did that several times didn't make any difference though cause even if the filament fed in still the same issue