Okay, here it is... I did some more diagnostics and this is what I found. The plugs continue to spark even though there is no injector pulse. This only indicates that the secondary side of the distributor is good. It was very difficult to test the pickup because of where it is located, but it was original and was looking rather poor.
I pulled the distributor and replaced the pickup with genuine AC Delco. I reset everything and still starts and runs fine when the engine is cold and continues to run great when hot, no codes, stabile idle with great throttle response, but will not start if you turn it off and try to restart. When engine gets cold it will start again just fine.
I grounded the cold start injector and 'wallah' it now starts normal hot or cold. The cold start injector is on an entirely seperate circuit from the other injectors and is designed to 'enrich' the cylinders when the engine is cold to help it start easier in cold weather. The cold start sensor will only allow the injector to run for eight seconds and then it cuts off. It also has a temperature sensor thet cuts it off when the engine temperature is 95 or above. The engine relies on the port injectors to be able to start it under normal operating conditions. These injectors get their pulse from the ECM via an input signal from the Ignition Control Module. I Ohm'd the harness from the distributor to the ECM and although I am unaware of a spec, it all tests normal. I replaced the coil side of the harness and the radio noise suppressor previously. I tested the 8 injectors, and tested for pulse on both sides while all were disconnected to eliminate a shorted injector, (none). I even tested the O2 sensor for a short, even though it too is new Delco.
The port injectors should pulse, even at the 450-500 rpm the starter turns it over, but they do not. With the cold start injector to enrich the cylinders, it will start every time, and the port injectors pulse as soon as the engine starts. I cannot understand this. It makes no sense at all.
I refuse to believe that in 20 years of these TPI systems being around that I am the only one to have this problem. What say you?