Hi all. I am changing the spark plugs on my 1999 5.4. The plug that came out is a motorcraft 22E, the threads are shorter than the motorcraft sp 479 that it calls for. I don't want to put these new plugs in until i am sure . thanks Gary

 

They are correct. There was an update done to the plugs. SP-479 is what you need.

 

Thank you very much !!!

 

Those plugs are very very old. The update was done over a decade ago.

 

No problem. FYI - Ford added more threads in an effort to prevent sprak plug blowout. If you hold them side by side, you wiil notice that the seat is still in the same position, so the depth of the plug remains the same.

 

I got 15 years out of my first set of plugs.

 

Years is not so important for ceramic and steel.
How many miles on those plugs?
Plastic and rubber parts do have issues with age.
I have 2 Explorers '92 & '93, both with 110-115k.
Interesting that both radiator tanks started leaking last year.
I wonder how long the plastic intake manifold and radiator tanks on our 2003 5.4L will last, it has 174k.

 

It was 90k on a set of OEM plugs - one of the coils started failing at the OD speed so I replaced everything - runs so sweet now except for the massive rust everywhere

 

You may not have had a bad coil.
The boots deteriorate long before the coils go bad.
I change plugs and boots at 50k.
Denso 671-0001 boots have worked well for me.
Changing plugs at 50k reduces the risk that one will work loose and blow out.
Most of my coils are still OEM at 174k.

 

DOH! I wish I had known that but new plugs and coils were less than $100 so I'm able to recover from that buyer remorse. I kept the coils for future use.