1995 Pontiac Sunfire No check engine light, won't start

Car stalled occasionally when hitting bumps, pulled in driveway like normal, went out next day car no start. Towed car to garage, removed coils and ecm, had tested, still good, put back on, car ran about 45-60 seconds, check engine light flickered then the car quit, and the check engine light has never come back on, nor is there any spark to the spark plugs. I have replaced crank sensor, coils, plugs, wires, fuel filter, tried another used computer, ignition switch, checked all fuses and relays three times, I have hooked up an obd II autoscanner and get an error message check connections. I've used test light power is getting to ecm and to pcm, suspect bad ground also fuel pump doesn't sound like its working anymore? Can anyone give any help to this nightmare? Or can you explain why the check engine light won't come back on?