1989 Buick Century Catalytic Converter/Oxygen Sensor/Spark

I have a problem with my car, I was driving yesterday when it began to sputter and tried to stall, I applied the gas to it and it stopped. I went to the auto parts store for some oil and coolant, tried to start it up and had to crank it over six times. It would stay running for about three seconds or so. I got it home, after the Service Engine Soon light came on. And opened the hood up, unplugged the spark plug wires, re attached them all, and started up, the light then went out for about five minutes. I idled the motor back up and the car acted like it was gonna stall out again, I got out and all I could smell was raw gas in the exhaust. Then today we check the spark plugs out again. Unplugged the spark plug wire from the bottom of the front of the motor, and the car stayed running, all the others when unplugged made it stall out. Any suggestions? This vehicle is a 1989 Buick Century Custom 3.3L V6 Motor, with 205,000 miles on it. Please help.