[iamhelpfull]

I have a 2000 F150 automatic , V-6 with about 180,000 miles...it sounds like the valves are knocking, no real rhyme or reason as to when I hear this...even with High Test gas, but doesn't seem as bad. I've replaced the plugs with top of the line platinum and new wires but knocking started back after about 10 miles. Brought it back to the shop and found #2 cylinder plug was fouled out. Mainly hear it when starting off, but if I get on it, there is no problem or knocking. I change the oil every 5,000 with synthetic. Several mechanics have looked at it, but no solid conclusions...dang, I'm about to pull my hair out. Can anyone help me?