1989 Chevrolet Celebrity will not run

1989 Chevrolet Celebrity 2.8 mileage: 179,000. First, it is hard to start without pushing the pedal to the floor, and then it will run but very erratic. I have to keep pressure on the pedal to keep it running. Even with pressure on the pedal it will just die. The engine light does not come on until the engine starts to run erratic and then dies. The code reader says 12. My neighbor seems to think it might be the catalytic converter. The Torque Converter lock-up switch is disconnected and I even tried the test with the ERG valve disconnected. It has new wires and plugs, and O2 sensor. There is a tube that runs from the valve cover to what looks like the Throttle Body, but when the car is running it has no vacuum. Any ideas?