I had this problem with a 3 liter last month- replaced the plugs, wires, coil pack, and even two injectors- nothing. Gave up and sent it to the repair shop. In the end the problem was a faulty NEW spark plug.
Try swapping the number 6 plug with another cylinder and check if the misfire follows it.
1995 T-Bird. PI 4.6. Bullitt intake. Big MHS cams. 4,200 Dirty Dogg converter. Kooks headers. Full exhaust. 4" Drive Shaft. 4:10s.
Waiting on a tune.
1997 Lincoln Mark VIII FX2 Sand Dune Machine.
1997 Lincoln Mark VIII LSC- stock