2006 f 350 diesel starts when cold and does not when hot and laso runs rough

2006 ford diesel 6 .o starts when it is cold but will not when engine warms up and run rough

Hi, I have replaced HPOP, stand pipes, dummy Plugs, trucjk starts great when cold, won't start at all when hot. ICP-DSD 4000kpa and ICP Actual is 2500kpa when hot, What can my problem be, thanks
Boe