I have a strange problem. I can load a filament. Start a standard print that comes with the Prusu is3. It get’s two or three cm off the ground. perfect print, no problem. Then the motors stop feeding the filament. If I give it a push it starts extruding again, but by the force of my hand. I cleaned the head with needle. The code is fine because this happened three times, built to different height each time and then just goes up as if the filament is coming. So all the motors are good.