No Fuel Injector Pulse When Engine Primes

What is your question?

1990 Chevy Suburban, V1500 with a 5,7L V8, TBI. The fuel injectors wont pulse when the fuel pump primes. No matter how long i crank the engine the injectors will not pulse. However, when i spray starter fluid down the throttle body when cranking, the engine fires right up. After which the fuel injectors will start to pulse. But, after start up the engine will go into a high idle of 1800rpm most cases. Following that the engine will gradually pick a lower idle till it eventually stalls. I have replaced the ECM multiple times, including the ICM, coil, fuel injectors, fuel pump, and fuel pump relay. I do have an OBD check engine code come up randomly, CODE: 42- Oxygen sensor error (rich condition indicated). Could the possible issue be with the electronic spark control module?

What makes this problem better or worse?

Runs longer when NEW coolant temp sensors are disconnected

How long has your 1990 Chevrolet V1500 Suburban had this problem?

A few months