i have a 2003 f250 6.0l i am noramlly a drivability tech but have my deisel certs. our diesel tech is out sick and i have got a 6.0l that didnt build more than 180-190psi of icp. i tore off drivers side valve cover and applied air and heard escaping near rear of the head. figured pump fitting or oring would be leaking due to advise from other techs. tore down to high pressure pump check ball is still inside pump and smoke tested pump but found no leaks.also found icp leaking oil. at this point kinda assuming the icp is hanging up causing loss in icp needed. any ideas or other things or ways to check to make sure everything is ok with pump? or what other issues there could be?