I've got a 2003 f-150 4.2L V6 4x4, 5-speed manual. I've been trying to fix my truck for the last couple days with no luck. It shifts through all gears fine and the engineer is running smooth, but whenever I try and give it any power while at med rpm in any gears, it starts to slip and the engine will rev up and increase rpms. I've replaced the entire clutch assembly, clutch plate, slave cylinder, master cylinder, pilot bearing and flywheel. I've bled the system two times now and Ive let the truck idle and dropped the clutch and it kills the engine. I also put the truck in 4 high and Im still having the same issue. Any help would be appreciated.