GMC suburban 1999 6.5l won't start
 

Truck has 122K. From Florida which I'm back home, truck stuck in Columbus Georgia with dealer. I get a call that diesel mechanic at dealer doesn't have experience with the older diesels (say WHAT). Back to square 1. Told me to come pick it up. History with truck. About PMD, replaced and relocated on heat sink about two years ago due to truck not starting. Fixed and running great. Then LP goes bad in South Carolina, replace (ac delco), change fuel filter and truck runs fine. Ran great for several thousand miles then had issue with irractic idle and runaway throttle. Call numerious repair shops and they point to IP ($2300). So I replaced with another PMD (find out later remanufactured pmd) based on info from forum. Ran fine for 700 miles. Truck then starts to intermittenly stop with sometimes hard starts. Replaced PMD (returned other 1 with another remanufacture warrantied) again due to symptoms just before trip to Georgia. Ran great all the way to Georgia and we know what happens then. Shut down truck in parking lot and won't restart. Same symptoms as those other bad PMD's. Run to parts store replace with a Dorman PMD (not remanufacture). To my surprise, doesn't fix the issue. Truck won't start. What can I look at to get my truck running again. Could it have been a faulty PMD I bought when I was there? What can burn out a PMD. Maybe that is where I need to look. Please help with any info. Hard to believe 3 pmd's in such a short period.:argh:

Stuck Truck
 

Some of what your describing sounds like something I experienced not too long ago. PMD, Lift pump, Fuel Filter, IP nothing fixed it and local shops were clueless other than asking for my CC.
What I noticed was the bottom of the filter housing had lots of muck and my filter seemed to be clogged, when I tried the water bleed/ T valve no fuel would bleed off. As I traces out the fuel & return lines they seemed very corroded. When I dropped the Tank and fuel lines I found they were plugged and rusted out. Wile I had the tank down I replaced the sending unit and took the sock off, but I did add an additional fuel filter in-line by the rear wheel.
Not saying this is what you are experiencing but sharing a story about my own hair loss.
:tu:
There is a great section here about troubleshooting the 6.5 that helped me through a lot of my pain.
Good Luck!!!!

more than likely its your pmd i got a shit 5 also and no matter what those things are always going out no matter which one you buy. they go out because of heat from the motor where do you have yours located if under hood i would really really suggest relocating the pmd inside the truck under the dash or in the back of the front bumper. i havent had a problem with mine in 2 years now since i relocated it. I went through 3 of them in 4 months but since i did that no problems