I have a 1993 Chevy 2500 6.5 Turbo Diesel with 250K miles vin code F. My problem is my truck is hard to start and when it does it will run for a couple of minutes then it will RPM up slightly and die. I have replaced the fuel pump and the fuel pump relay but still have the same proble. I have noticed there is a rubber vacuum type hose hanging down from the transmission with what appears to be a melted fitting on the end, don't know if this has anything to do with mu problem. Any help is appreciated.

 

Have you checked your fuel filter, sometimes it helps to replace it. Also you may have air in the system, open your T- valve its by the thermostat housing and see how is the flow. Also check your OPS, Oil Pressure Sender switch its right where the glow plug controller is. Also just go trough the electrical connections, I know that the fuel pump shut off solenoid gave me a lot of grief before, there is a single pink wire right on top of the Injection Pump, I believe its on the left side when you're facing the truck. Hope it helps, I know I have always been told to rule out all of the smaller and less expensive items before, major stuff.

 

Yes I have replaced my fuel filter, I will double check all of my electrical connections.