2003 F450 S/D 6.0 knocks off while driving

[1fast93stang]

I have a 2003 F450 Super Duty with the 6.0 diesel and the truck has never given me the first bit of trouble until now....I was going down the highway and the truck just knocked off like as if I turned the key off but still had all my dash lights etc., I rolled to the shoulder and hit the key and it went about another mile or so and did the same thing, I got it back to the shop and now it will only stay running for a couple minutes at a time. I was told to change the ICP sensor and I did but the problem still persists. I am not getting a check light so I cant dump the codes and I don't know what else to look for or check ! Any body have similiar issues ? or do any of ya'll work on these trucks and know what to look for ? Any help wiould be very appreciated, Thanks in advance. Rick

[Surge08]

what kind of pressure are you getting out of the High Pressure pump?