Ford has a real serious problem now but it has nothing to do with this OP's problem.
The Fords with the Triton 5.4L v8s and some of the other engines (V-10's) had 1/2 inch reach spark plugs in their aluminum cylinder heads. Starting about 1996 up to 2004. These engines would literally blow the spark plugs right out of the engine and break the coil in the process. The fix was a special 4 piece tool kit that cost almost $400.00 and it would rethread and prepare the cylinder head for a Tinesert.
A company called CAL-VAn made a better version that recut the threads with 2 tools and used a thicker wall insert. Many owners had more than one plug blow out. It happened to my van. Ford said it would be $1700.00 to repair it and $7,200 for a new engine.
I thought of buying a V6 engine Ford van but found out you have to remove the intake manifold just to change the spark plugs. Forget that!
In 2004 Ford redesigned the cylinder head and had a special spark plug manufactured that had a metal shield that extended downward on the spark plug. But when it came time to change the spark plug it would break off in the cylinder head. Then Ford said you had to soak the spark plug in penetrant for one hour while the engine was still warm then remove the plug and hope it would not break off.
A special tool kit was designed to remove these special broken off spark plugs.
Now Ford says it will only replace the cylinder heads on the 1996-2004 engines but to do it they remove the entire truck body so they can have access to the engine.
When the spark plug blew out of my 1999 1 ton E350 ford van it was the #2 plug. There was a loud BANG then a flap...flap...flap noise. My OBDII confirmed a misfire on #2 cylinder. The plug was loose and the coil was broken off but because of the body and engine style I could not even get the plug out of the space it was loosely sitting in. I sold the van for scrap.
I bought a Chevy van .
Below is the special spark plug Ford had designed and a broken one.
The night it happened I stayed up all night reading similar stories by other owners.
Many other owners same problem. Plugs blowing out of cylinder heads.
Almost ALL other engines with aluminum cylinder heads have 3/4 inch reach plugs. Except Ford.
On a Roadstar Adventure.