A bit more 4.6/5.4/6.8 Plug Issues

[Arnold]

I did a quick bit of research.
  Appears that the problem started in 1997.
 There are no common reasons why the plugs blow out. Nothing one can do.
  Apparently the root cause of the problem is BOTH faulty castings AND poor tapping of the plug hole. At random during production.
  There is really no way in knowing what a good or bad head is.
 Thread inserts sometimes do blow out too! because the parent material in the head is no good at that point.
 Around 2002 the length of the threads in the head was increased from 4 threads. From around 2002 for about  a few years there were no problems.
 When the 3 valve heads came out the problem came back! If you do a very quick read..yes these were the years/heads were GETTING THE PLUGS OUT was the problem. That was where the focus WAS. Read a little more and it becomes very obvious that these things blew out plugs just like the older ones. The 3 valve heads NOW had BOTH problems.
 
 Looks like the problem is almost non existent from 2005-2008.

  Just thought seeing as how the thread went..I would pass this along.

[purplepickup]

Thanks Arnold.  I'd read some of that too.  I hope I got the good castings.

Winter is almost here now and I probably won't mess with it til next spring, since it's a 'summer only' ride.  I'm keeping my fingers crossed that I learn enough by then to avoid a problem.

[wvcab]

you probably already know this but.... use anti-seize on the threads

[Crosley.In.AZ]

I removed the spark plugs from my 2001 F-150 engine 5.4 at early mileage ( 20k or less) I added anti-sieze to threads.

Around 65k miles the truck started to eat the coils on each plug. I checked online and learned it was not un-common for the coils to go bad at that mileage. The engine would develop a slight stutter, then shortly a cylinder would mis-fire

The member Glen on RRT helped me with acquiring new OE parts. By 69k miles the truck was traded off.

Also , around  28 k miles, the front brakes were worn out... also considered normal on a 2wd F-150 truck

[rooster]

Here's a guy that had all 8 plugs brake, It was in a 07 f150!