Dies for no apparent reason and wont start for a while.

My truck will run like a top.I can run 20-30 minutes and stop.When I go back to crank it sometimes it wont crank sometimes it will.When it does crank it runs fine.It died once going down the street and acted like it lost all power.The only thing I hav'nt checked or replaced is the Fuel pressure regulator or the injectors.Everything else related to the fire or fuel has been replaced with the exception of the ignition coil module.Its got me puzzled.It is not setting a code either.Prior to this it had been bogging down and both converters were replaced.Runs great until it dies when least expected.When it wont start it is getting fire and the fuel pressure is at 60 psi.Any body ever have this problem?This is a V-6 4.3 chevy truck 2000 model.When it does crank after dieing it seems to crank better with the breather off.I noticed the fuel line fitting on the filter was moist but not dripping.I'm fixin to tighten it but the pressure is good.Any replys would be appreciated.

Sometimes when the fuel pumps are dieing they tend to stop working until they cool down, does this happen with a full tamk of gas or under half a tank only?

Right now it has about a 1/2 tank of fuel .also I replaced the pump about 2 weeks ago.I checked the pressure this morning and it was 60 psi and still would not start.Checked the coil and did not seem to have any fire.My son was turning the ignition over while i was attempting to pull the vacum hose off the breather and also grabbed the coil wire at the same time and bam.It started.Running fine now and no codes.Dont know what it is yet but I am beginning to think its fireing problem instead of a fuel problem when it dies.The coil is also about 2 weeks old as well as the wires and pluggs .rotor and cap.I have not changed the Ign.coil module.Dont even know what it does.Any ideas will be appreciated.