1995 chevy 5.7 tbi nightmare

This truck when started cold will run perfectly, once it has been thoroughly warmed shut off and restarted it will begin quitting, it will not "sputter" but completely quit as if someone has turned off the ignition. Some days are worse than others, When I have enough rpm (highway driving) or a good amount of throttle) it will hesitate, or stutter but regain power, it basically tries to shut off, but because their is enough rpm and speed it catches itself and stays running. If it quits I will just throw it in neutral start it, put it back in gear and resume, It always starts right away even after it has failed leading me to believe that it has to do with (spark) not (lack of fuel). this issue is especially prominent after pulling up to a stop sign, and as soon as the light turns green ill put throttle on, and it will die, put it back in neutral get about 2,000 rpm place in drive (quickly). it really doesnt have a preference when it decides to misbehave, but at low rpm, it just seems to die with more frequency. like i stated above enough rpm and constant throttle wont allow it to completely quit, It will lost power tach reading zero and 1 or 2 seconds later engine will resume normally. There is definitely something going on when it gets warm, but what doesn't make sense is that after the engine is cold and warmed to normal operating temperature it will operate AT the temperature for Miles, and miles until it is turned off, and turned back on. This truck will always start, plenty of power, does not smoke. I have had this truck to the shop twice, I asked them about the possibilities of other components being faulty Iac, tps, map,ecm and they seemed to believe the new distributor was at fault so I replaced it again. Its very difficult to troubleshoot at the shop because, its so hit and miss when it comes to behaving badly, i think they make a repair, ( test run the vehicle while cold) and believe the issue is fixed. I have also played with the timing, had the timing chain checked also, I Do believe that this engine itself is okay, I have no idea what else to try at this point, I do not want to start replacing iac,map,tps etc without at least a general idea as to what might be causing this.. Please Please im begging you throw me some Ideas. Also the first time i took this to the shop they said it had low fuel pressure so they replaced the filter, I took it come and replaced the in tank pump as well, I assume being a new pump that the pressure is where it needs to be but I have not had it tested again...
1. New Plugs
2. New Wires
3. New distributor (2x) entire assem
4. New Fuel Filter
5. New Fuel Pump
6. new Air filter
7. New ignition Coil