95 7.3 power stroke intermitent no start

[Don Weston]

My 7.3 has failed to start on three occasions this week. I can usually get to my original destination, but the truck will not restart. The starter spins fine, but it will not fire. If I let it set a few hours, it will start and run normal. I took it to the local dealer and they replaced the alternator. Said it was only working part of the time. Drove it home and could not get it to restart. Took back to dealer next day and they found code P1212 for an injector pressure regulator. They said it was stuck, but didn't know which one to replace. They ordered both and will try it. My question is did the injector pressure regulator fail and correct itself three times, or is something else causing the fuel delivery to stop creating a false code for the pressure regulator. I would think I am dealing with an electrical problem with fuel delivery such as a solenoid or relay or possibly a crank shaft sensor or throttle position sensor failure. Any ideas on why the truck will start and run fine after sitting for a few hours? I can't afford the service charges and parts for my Ford dealer to guess at what could be the problem.

[Don Weston]

The IRP was replaced today and seems to be working fine. The service tech used ice water on the IRP while it was stuck and this allowed the truck to start. I have been using bio-diesel and was wondering if this could contribute to the stuck IRP? Is there a good fuel conditioner that is safe to use?