98' 6.5 died and won't start
 

Replaced and relocated the PMD to the front of the radiator a little over a year ago after the truck died while driving. The truck ran fine for a year and then did the exact sane thing. I took it to the shop suspecting the PMD was failing again. They diagnosed it as a FSS failure. About a month after getting the truck back, the symptoms started again to the point that I could barely get out of the driveway. I had the truck towed back to the shop where they could not replicate the problem. There is no engine light and no codes on the download. I left it with them for a month and a half to use as their shop vehicle with an OBD on it and they never had the problem occur.

Fast forward a month and I pick up the truck with the OBD still on it to try and get the problem to reoccur. After two weeks, I noticed a fuel leak out of the bottom of the filter housing. Back to the shop to replace filter housing. I picked up the truck two weeks ago (they pulled the OBD off the truck). All was well until yesterday when it turned off just after cranking in a parking lot. It fired back up immediately, but died after driving around a mile and will not start. When it dies it is just as if you turned the key off. All symptoms seem to point at the PMD again. Is this likely given the relocation and age of the PMD (one year)? What else should I look at to find the right part? Any help would be greatly appreciated.

I had the same issue with my 98 years ago. It would shut off at random times even at 75 mph on the interstate. After throwing a pmd and alot of other crap at it...turned out to be a faulty ignition switch.

I don't know of any diagnosis for a faulty ignition but it wouldn't cost a lot to replace it. Worth a shot.

If the instrument cluster dies at the same time the truck does but radio and blower motor keep working,the ignition switch is the likely cause.

So, drug the truck back to the house this morning and it would crank all day long without firing off. Bought a new PMD and swapped it out. Truck fired right off. But, I then plugged the old PMD back in and it fired off as well. Dash lights seem normal, although I am not sure I have ever paid that much attention to their sequence for the 17 years I have been driving it. Any suggestions on if the PMD was the issue or not? Ignition switch is next...followed by a new truck. Thanks for the advice.

Use only an AC Delco or GM ignition switch.

Update...truck ran great for a day. Died yesterday at work. Drove 20 minutes to office, sat for about 3 hours and. Then when I cranked, it fired off for about 2 seconds then quit and would not start again (lights working fine on dash). Switched out PMDs at end of extension with no effect. Truck stayed at work overnight. This morning prior to having it towed, I tried to start it and it would not fire. Next, I plugged a PMD into the harness at the IP (bypassed the extension) and it fired right up. I then however reconnected the extension harness and it ran normally as well. It is almost like a short in the extension and once you get the truck running, seems to reset for a bit. Drove it 15 minutes to the shop as I am completely out of ideas.

Issue turned out to be female connector at the IP. Had that pigtail connection hard wired and good to go.

I am going thru similar things with my 98. Replaced PMD and extension harness , and it still randomly runs and dies.
Pulling out my hair.
Replacing the female plug might be a good idea, for me to try
.

Cough Cough Throttle Peddle. Oh yeah its electronic and will cause your 6.5 to die and not start, rev and all kinds of other fun stuff. Another thing that could be doing it is metal/rust flake interfering with the cam sensor. Oh yeah the $4500 piece of rust that hangs in my buddies shop is the classic example of that one.