I need help with my stealth

Why did you replace the ECU and not the ignition coils?

TEST IGN COILS

Yes there are only a few possibilities for a no spark condition. The ecu reads the cam signal and determines when to signal the ptu, which then fires the coilpack that is connected to the plug. So it goes ecu, ptu, coilpack, wires, plugs. The ecus 91-93 all had leaking capacitors on the boards, so you also need to make sure you have a known good ecu.