had a miss then clacking noise

[Fisheye's]

I'm new here and not real good on deisel's. My truck has been leaking fuel I've replaced all the hoses and the o-rings in the fuel/water canister and it still leaks fuel down the torque converter cover. The other day it was running fine pulled in to park went to back up to get a straight shot into the parking space and it started to miss so I put it into park and lightly gave it a rev, it smoothed out and I parked. Later I went to run an errand and it started up fine but as I took off it started to miss I was able to get it up to freeway speed with periodical misses and I made back but noticed a clacking noise that wasn't there before. Someone said that it was the fuel pump going bad, would that make the engine clack? Not sure what to look for the truck has 245k and nothing ever done except a water pump and routine maintenance.
Can someone please give me an idea on where to start.

[Deeslfxr]

What year is it? Pre-'99 had a mech pump in the engine valley. Post-'99 had an electric pump on left frame rail. Fuel leaks can cause pressure loss and possible aeration of the fuel. As far as the noise, pre-'99 had a belt driven vacuum pump that would make a 'clacking' noise when it was failing, whereas post-'99 did away with this system.

[Fisheye's]

It's a 1997 and I've replaced the lift pump in the valley that was a pain in the _ _ _.
From everything I've read your'e supposed to remove the turbo to replace it but after several hours of work I managed to change it without doing so just several colorful words and a couple of busted knuckles. So it's possible the clacking noise is coming from the vacuum pump?

[Deeslfxr]

[QUOTE=So it's possible the clacking noise is coming from the vacuum pump?[/QUOTE]
Yes, remove the belt, start it up and see if the clacking noise goes away.