Farmtrac 535 Fuel Problem

[TR16]

I have a Farmtrac 535 that sounds like it's fuel starved at 1/2 throttle or more. When idling, runs smooth. When you give it half throttle or more it starts sputtering. Almost sounds like a miss in the engine. When I pump the fuel feed pump manually, it levels out and sounds great for a few seconds then goes back to sputtering. Makes me think fuel is not getting to the injector pump. I disconnected the feed coming from the fuel tank, strated the engine, and fuel flow looks great. But when I disconnected the pipe on the other side of the feed pump (running from the fuel feed pump to the filters) and then started the engine, there is no fuel flow at all. It seems obvious that the feed pump is bad but I'm thinking that's too apparent. I took the feed pump off and there's really nothing to it. I don't see how it can go bad.

Can a fuel feed pump go bad? Or is there something that pulls a vacuum that I need to be looking for?

TR