Ford #2 cylinder misfire

I have a 1997 F150 4x4 with 4.6 V8. I get the trouble code #2 cylinder misfire. I have changed plugs, wires, injecors, crankshaft position sensor, changed the fuel filter and tested the coil with a multimeter and it checks out ok. The engine runs rough and is definately missing on #2 cylinder. I can unplug the #2 spark plug wire with no difference in performance, leading me to believe there is definately something wrong in #2 cylinder. What have I missed, any help is much appreciated.