[Davescort97]

Chances are fairly slim that the plugs or wires wouild be bad again in such short of time. It does sound like it is running on 3 cylinders. Could be a spark plug boot is loose on the insulator causing a misfire for that cylinder. You can tell which cylinder by pulling wires one by one and when the sound of the motor doesn't change after pulling the wire you will know that is the bad cylinder. When you find the bad cylinder, pull the spark plug and check the gap. Has it been mashed down. Couild be from a dropped valve seat for that cylinder. When you have the plug out ground it while the engine is running to see if it is firing. If it is you have a compression problem which will indicate major engine damage. Not the cat if you don't get a CEL code on it. Take it to Auto Zone if one is in your neck of the woods and get the codes pulled. Once you have, post them and we will determine what is at fault. They won't charge you at AZ to get the codes pulled. They will charge you at Ford.