Fuel pump failure?
 

I have a 1994 CPI engine that has a slightly rough idle. I dont have any black fumes or anything coming from the exhaust. I opened up the intake plenum and couldn't smell any fuel but it looked like at one point the FPR was leaking becuase on the lower intake wall opposite the fpr it was clean and everywhere else was carboned up. So i put in a new FPR. I dont have the smell of fuel coming from the truck at all. I just replaced the plugs and wires a week ago but this problem was present before. The distrubuter cap is about a year old aftermarket. With key on engine off i have 58psi on the nose, with engine idleing I have 54 psi but the guage flutters, When i first rev it up the pressure goes to 60 psi but then falls to around 50psi. I am probably going to put a fuel pump in it because when i picked the truck up in mass and drove it on my car trailer it started right up. But when i got it home all it would do is crank. So i got out of the truck and banged on the fuel tank with a rubber mallot and bingo it started right up. Anyone have any ideas. Also i have about 15 inches of vacuum at idle but just off idle i have 20 inches of vacuum... Any ideas would be appreciated. If i remove a vacuum line in runs 100%. I already cleaned the EGR valve. I can here the fuel pump grinding and if i put my hands on the fuel high pressue line it feels as if the fuel is surging through the line.