John deere 6410 misfire

[kdm700]

Hello to all I'm new here, hope I can help people and get some help for myself. I've got a 2000 JD 6410 it acts like its got a misfire but when I block the lines all 4 injectors are firing the same and there is no change in its sound, it's like it's got a 5th cylinder that's not firing that it doesn't have. I've got 6psi fuel pressure no smoke no pop just runs rough anybody every sen this before, new injectors injection pump lift pump and lines about 100 hrs ago