I had a 2007 F-150 with the 3V heads. The issue was that the plugs were 2-piece plugs that had a long nose that went deep into the head. Over time, carbon would build up in the gap between the head and the plug, and when you tried to remove it, the plug would be trapped my the carbon and would break. There is a special Lisle tool kit for removing the broken plugs. I broke 4 when I changed mine. When installing new plugs, you could either coat the plug nose (unthreaded) with nickel anti-seize, or use Champion 1-piece plugs. I used the Champions for a while, then replaced them with Motorcrafts & anti-seize. Ended up trading the F-150 for my XSport.