I have a 1991 oldsmobile cutlass ciera

Try changing your fuel filter and add injector cleaner to your gas tank

The ECM on this car will shut down the injector driver circuit if one of the six injectors has a coil out of tolerance. (Shorted coil or resistance out of parameters) Quick check. Unplug two wire cap to injector one at a time. (hold/push wire clip inwards then gently wiggle/lift cap off---careful with wires) With one unplugged try starting. If no start- plug back and use same procedure on next injector and so on.........In most cases if bad injector coil the engine will start when it is located. Replace injector. Some say the ECM shuts dirver circuit down to prevent further damage to switching circuit.

Crank sensor in the engine could be becoming oil logged. works fine when cold. fails when it gets warm. accessable on the back of the engine between the engine and transmission.

check ur igniter module it needs to be replaced or ur wirerinb to the module

Sounds like idle air control or cam position sensor. Throttle control valve(sensor)?

The Oxygen sensor is very suspect. it is easy to damage on install, even with the correct tool.

Put the old one back in and test the car...

replace crank sensor. It gets hot and stops working.

speed sensor on the transmission.

replace blower control module

I have no spark. Changed the CSS and still no spark. I also changed the Coil packs with a junk yard 1. Does anything else control spark other then ECM?
Thanks