91 sunbird (please help)

I was driving down the highway and all of a sudden my car just starts slowing down I try hittin the gas more and nothin once I stopped it stalled. Now it wont start unless I put the pedal to the floor and even then it runs really rough then as soon as I let off it stalls. I have replaced fuel pump, fuel filter, tps, computer, prom chip, idle air control, fuel injector, new plugs, new wires, and tested O2 sensors, map sensor, and egr valve. I'm getting spark and plenty of fuel, in fact I think its running rich. Any ideas on what I should do next would help a lot. thanks.