Will not run or idle once warm (sometimes)

Hey there, I have a 1993 F-150 with the 4.9 Straight six with about 140,000 miles on it. This truck has been great over the past four years, but these past two weeks have been kicking my butt. The problem is that the truck runs great, idles smooth and excellerates like it should, but without notice it will drop off and die out. If I try to restart it, it will not idle, but if I let it sit for a while (30 min) it will run great again for a few miles or a few days. I have already replaced the Fuel filter, Ignition coil, Fuel pressure regulator, Fuel pump, spark plugs and O-2 sensor. After the fuel pump repacement (BOSCH) the truck ran for four days, the longest between stalling out. (all problems have occured at different speeds and situations) Also the fuel pressure is steady at 48psi. With both the old and new fuel pump. So what do you guys think? I have used all my knowledge and am looking for your guidance.
UPDATE: I just changed the igniton control module (TFI module) and it died again. This time I hooked up the fuel pressure tester and was reading 48psi even as it was dying. Also changed the plug wires, cap and rotor to no avail. One other thing is that I do not get an "engine" light until the truck has compleatly shut down, so I don't think anything codes are being sent.
UPDATE: Replaced the EGR positon sensor and the idle air control valve this weekend due to the advise of the guys at the parts store. That seemed to fix it and it was free advise. I spent 20 bucks in donations here and got advise that my inerta switch was failing even though I posted that I still had good fuel pressure. This site did nothing but piss me off.