Rough running

Hey fellas, I have a 1994 chevy camaro 3.4l 140k. I have been going crazy with this thing. It starts fine and runs pretty good for about 10 minutes or so then it starts tripping. It sputters and cuts out and is undrivable. It does this in or out of gear once it begins to act up. I have replaced the fuel filter, fuel pump, fuel pump relay( which I can hear clicking on and off when it acts up), coil packs, plug wires, plugs, map sensor, air temp sensor, cleaned and checked the grounds and cleaned the fuel injectors. It seems to be an elecrtical problem, because it is intermitant. I am suspiscious of the pcm but I don't know how to check it. I have taken it to two GM dealers and they cannot detect any problem. Any suggestions?