To confirm or deny your assumptions about a dead cylinder assume the position and demeanor of PLASTI-MAN and try the following:
- Reach around backside of intake manifold with truck running and pull off a plug wire (off the distributor) one at a time (with truck idling) when you pull off a wire it should idle MUCH WORSE, probably even die, if it doesnt then you have no spark to that cylinder, it MAY help to have someone put a small load on the engine(truck in gear, foot on brake), sometimes idling isnt enough. <WARNING, make sure you do this with a pair of pliers or gloves or something to insulate your hand from the 30,000+ volts at cap>
Also, on same note.. Have you taken off the cap and rotor and inspected everything ? At the nats this year Ryan R's ODDFIRE engine wouldnt start at track, we traced it down to the fact that the rotor had come loose and attacked the inside of the cap, breaking off parts and pieces. (not saying you screwed up, but we all make mistakes)
Another option <truck OFF> to make sure there is spark at every cylinder is to take a plug wire OFF at the plug end (secured at distributor end) place a phillips screwdriver up the boot (where plug gets inserted) and then holding the insulated handle hold it a small distance away from a header,exhaust manfold, block etc, something grounded then turn truck over (have an assistant handy) and watch for a small blue spark. NO SPARK = PROBLEM you may have to crank engine over a couple times to see it, but it should be apparent EVEN in daylight. This will allow you to somewhat check the condition of your wires too. YES its possible to get a bum wire in a brand new set, but this will atleast allow you to "SEE" if there is sufficient spark. More than likely you will be holding end of screwdriver far enough away that if it lights in ambient air, it should light the plugs in the cylinder.
- If the previous step doesnt really show any results then one by one see if you can remove an injector harness wire from an injector, once again an assistant and a small load should really illuminate this problem. If you pull the plug, essentially disabling the injector then it should run noticeable WORSE. No change = dead injector.
And if you are comletely LAZY (like me 
)and LOADED with CASH (definitely NOT like me ) you can do the following:
- There are Infrared thermometers out there that will read well up into engine temps (exhaust temps more appropriately).. Alot of racing teams have them, you simply shoot at the exhaust header/manifold near the head and watch for some desparity in temps... Obviously a dead cylinder WONT be generating as much heat as the other running ones nearest it.. It should be a noticeable difference.
As far as the fluctuating FP, did U remove the part just upstream of the fuel pump in the sending unit ? I believe its called a pulsator ?????? Just about everyone I have talked to STRONGLY suggests its removal. Apparently these are known for leakage etc. If the pump is keeping up at running speeds it should NOT be an issue (meaning where you are having this issue).
However stranger things HAVE happened. If the pulsator is still there I would suggest removal. If not, then look for some reason why its varying soo much. Leak down should occur (fuel pressure) when truck is switched OFF but it shouldnt be instantaneous when pump is powered off..
Man I hope I havent confused you or made any of this worse.. Hoping it wont be much longer for me to have my truck running and I am dreading these problems if they appear..
Once again, I hope some of this made sense and helped remotely.
Good luck, lemme know if I can clarify any of it.
