So I just bought a '96 Suburban with a 6.5 Diesel, drove it back on an 8 hour trip with no problems. No I am having problems with it being hard to start, stalling randomly and throwing a engine code P0380. I have read some other post about similar problems, I have replaced the lift pump, it has a relocated PMD, and I have replaced the 'something" pump relay in the fuse box under the hood. Can anyone help me out?

 

ac delco ops to run your lift pump. and check for fuel leaks.

 

P0380 Glow Plug Circuit Performance

Check glow relay,coolant sensor wiring and continuity in the glow plug harness,each glow plug wire has fusible links that can blow as well as the fuel heater can blow a fuse if sorted out.

Also check for air in fuel by replacing the IP return line with clear diesel rated fuel line and with the truck idling-watch for bubbles.
Bubbles indicate that air is entering the fuel system normally between the fuel level in the tank and the LP-otherwise if it were after the LP it would be a leak.
Unless the filter housing is leaking fuel while parked and letting air in-could also be a combination of both?

Does the tank suck a lot of air when you refuel?
A plugged vent in the cap can also cause similar issues.