Originally Posted by boywonder
What year did the change to "newer style" heads occur??
Sometime in model year 2000, the newer heads can be identified by a PI mark cast into the head along the exhaust header side. That in and of itself isn't too significant regarding ejected spark plugs.
Originally Posted by longboardguy
My early 2002 v10 with original plugs blew 1 plug out at 120k. Faint ticking sound first, then engine warning light came, then it blew.
Ford Truck Enthusiasts is a great site all around for most things Ford related. I once contributed quite a bit there.
The linked article is great but I'd add its not definitive as to what exactly causes the ejections. My own conclusion/opinion is its related more to how plugs were initially installed.
The other issue how long plugs are left unchanged---too many believe this nonsense they're good for 100K or more. That might be as it relates to plugs still being viable for their job but after that interval we're having problems with corrosion and/or rust seeping into the threads making removal a nightmare.
The 50K interval has worked for me so far without any problems, knock on wood.
The faint ticking begins just after the plug becomes loose in its bore, sometimes sounds just like an exhaust stud has broken away.