starting problem ! ??

[ford crazy]

99 f-350 4x4 7.3L long block form ford 2.5 years ago has 22k on it this dang thing is driveing me nutts not to mention lots of $$$$$!. it been to the dealer 3 times for this problem in january the fuel heater went out blew the #30 fuse i unpluged it and it ran fine for a few more days and then it wouldnt start at all. towed it to ford dealer they said it starts fine every time they tryed it for 3 day they had it . they told me to come and get it couldnt fine any thing wrong . then 5 min later they called me back IT WONT START!!! 4 more days they said it was the # 8 inj Orings it ran fine for months once and awile it would take a little longer to start 2 weeks ago & trial and error still has same problem things i have tried new IDM,ICP,CPS,ECM,FUEL PUMP,FILTER AND IPR, now i have a good used one to sell with only 22k on it dam that makes me mad i talked to 3 ford cert diesel mecanics today and all 3 said it cant be the orings ??? it has to be the iPR ! now i wonder if it is the orings or forbid an inj they said when they had it the last time it passed the buzz test . the batterys are new and it rolls over normal they said the fuel pressure & HPOP pressure are in specs i should have kept my 2wd one help!!! im about to loose my temp on this one im about half tempted to take it to the crusher at this point im about to take it to them one more time and get !?@??!$$$(*) again any ideas ?