I guess from 2005 to 2008 Ford used a faulty spark plug in the 5.4L, 4.6L engines. When you try and remove them they break causing additional servicing. There is a FSB to help mitigate the problem but it appears it still fails a lot. Any way here is the FSB from another site:
You can find lots of forums and chats about this. Most are staying you should replace the plugs earlier than later, but be prepared to extract the broken parts or get it done at the Ford shop then pay $$$. I think most people are out of warranty when this hits. I've just started to read into this as well as I just got a new 08 Expy.
I guess from 2005 to 2008 Ford used faulty spark plugs that when they are tried to remove will break causing more servicing. The TSB has some ways to help mitigate this but it still seems to fail a lot. Here is a post from another forum that has the TSB. Lots of treads and forums are talking about this headache. I've just started to dig into it.
The TSB is attached to this thread near the bottom.
Thanks for the info! Now I'm figuring out if I should just change my plugs now to the 1 piece design, or just wait until the need changing and let the dealership do it..... I've got 11K on it and looks like you need to address it by around 15K or run the risk of breaking them later.
The Dealer will put the same 2 piece plugs back in. There is not a 1 piece replacement from the dealer for the 2 piece plug. How they address it is by coating the lower sheath, till about a 1/4" away from the igniter of the plug (not the Threads) with nickel anti-sieze to prevent carbon build up.
I have a 08 Mustang w/ the same plugs. I pulled them as per the SB and coated them as preventitive Mx. Stang only has 2000 miles so they came out real easy.