I have a HP 4000 that works fine until the paper tray gets down to the last few pages. Then it miss feeds. It happens before the fuser. The page gets turned crooked and comes out mangled. I tried replacing the , paper tray, Tray one/MP assembly, registration assembly, paper feed assembly. Separated the printer from the tray assembly and cleaned it all out. It still does it. No paper in the sensor area either. Any ideas?