1994 Other Saturn Models SC2 Engine not running

In the beginning, the engine was starting to falter at 1500 RPM's and above after warming to operating temperature. I took it to the dealer and they said the catalytic converter was bad. I replaced the catalytic converter but did not help. At this point, the only time the engine would run was at initial startup at idle, before warming to normal operating temperature. I replaced the plug wires and plugs - no help. I replaceed the fuel filter - no help. I checked the fuel pressure (around 40-45 psi) - no help. I replaced the fuel pressure regulator - no help. I replaced the fuel pump - no help. I replaced the PCM - no help. I checked the fuel injectors for pulse (correctly pulsing) - no help. At this point, the engine will try to fire at initial startup but will not run.