The ECU receives a start signal, and starter signal is applied to the STA terminal. It then send voltage to the fuel pump, the fuel pump switch in the airflow meter provides the ground for the relay on start up.
Fuel pressure PSI? Vacuum "at idle?.............?Knock sensor (single , in center under intake plenum) detects detonation and retards spark timing as needed. Common on those engines to have the wire harness get brittle and break during service/repairs. Would not be the primary cause of your symptoms , as described........Good luck. IF ABLE >>> take 24 hours to enjoy holiday and forget car..........the pause you take , may help you find the cause you seek!!
do you have a pressure gauge and proper adapter(s) to check & monitor fuel pressure , both with engine running and with engine off (use test connector in engine bay to operate fuel pump-key on -engine off). Get specs for fuel pressure and see what it is while not running , and how fast the pressure drops after shutting off fuel pump. Poor fuel pressure (although enough for it to run) may cause rich condition , due to injector pulse width being greater in order to compensate for the lack of pressure. Something else to do , just to help verify other conditions , would be to hook up a vacuum gauge to the intake (engine side of throttle plate) and watch reading. Post vacuum readings from both start-up , and as it warms up and under acceleration (in park-just revving to 3K) .Last thing- just to reiterate from earlier post you are POSITIVE about CAM timing?