PrairieTruck

I drive a 2000 Chev Crewcab K2500 5.7. The engine is a GM rebuilt that I had installed 100,000 kms ago. The odometer reads 285,000. Last summer the truck would simply die. A friend changed my distributor, crankshaft and camshaft sensors, and the fuel pump. It improved but still the odd dying. Okay during winter. Mild weather is back and it's doing the sam thing. The DTC says no codes but the I/M says O2S, HO2S and EGR are 'not ready'. I need to erase the codes to restart. Sometimes, I have to disconnect and reconnect the two top cables on the ECU to restart. Letting the truck cool off also allows a restart. I'm at a loss and don't know how to resolve this problem. Help anyone?