450C that loses power then dies after running a few minutes.

[RKAngel67]

Anyone who can tell me if the fuel pump is bad or do I need to replace the fuel injector pump?
I bought this 450C that had been sitting awhile. It was in very good shape except the paint. It will run good for a little bit, then loses power and eventually dies. It doesn't want to start up immediatly, but if I let it sit a little bit, it starts up, runs a little bit and starts doing the power loss all over again. I changed out the fuel line to the tank. I emptied almost all the old fuel. I ran Seafoam cleaner through with the new diesal fuel and I even replaced the fuel filter.
It still does the same thing. Anyone have any ideas?