I have replaced the coil pack with a motorcraft one and that did make a difference. I also gave it a seafoam treatment that made no difference.
The truck was purchased in January of 2003 so I don't think it is a late model build that would be covered in 2004. Is the best way to check the camshaft assembly just to take the whole thing out?
Some other details I have noticed when I drive it after the codes are cleared (or when it is cold) it runs pretty well until it warms up and then after a few more blocks I can feel a power loss and begins to run really rough. If it is under high load going up a hill or I rev to and hold at 4000 rpm occasionally I hear a noise like something rattling around. Almost like a bean in a can.
Could misfires be caused by a problem with the cat? | 
