83 spider is misfiring

we recently put 2 new fuel pumps on our 83 spider. now the car is missing really bad and has very little power. we changed the plugs and it didn't help. I pulled the plug wires off the plugs as the car was running and the car stopped running except when the #4 plug wire was removed the car kept on running, but we could still hear the #4 plug wire making a popping sound as if it were firing. So, do we have a bad plug wire. Please help.