6.2 Diesel problems

[Mattman2010]

I have a 1980 chevy k10 that I swapped a 84 Military blazer 6.2 into and it has been running fine for the past year. But last week it quit running. I put more fuel in it (gauge is tricky at times) and I am getting a good flow of fuel out of the filter mounted to the firewall. I noticed lately even on warmer days that the engine needed 10 seconds of glow plugs, crank, and 10 more seconds of glow plugs and it would fire right up. I have also noticed that when you let off the throttle it does not "fuel down" as fast. Before when you let off the throttle you could feel the truck slow down pretty fast. I have fuel and I have 12volts to the injection pump. When the truck quit running it was running really sluggish and then just died and would not fire back up. Is the injection pump bad?

Thanks, Matt