5.4 and spark plugs...

[90MarkVII]

Gentlemen,
What years of the 5.4 (and 4.6 for that matter) were prone to blow out the spark plugs and/or prone to breaking the plug off in the head?
Thanks.

[black50]

99-early 03 - 4 thread heads

The fix was done in late 2002...so the early 2003 models also had the 4 thread heads..I believe the 4 threaded heads were being put into 03 models up until december of 02

after that the 05-06 models were fitted with a 2 piece spark plug that was prone to breaking off in the head

I have a 03 lightning that was built in Feb 03 and has the 8 thread heads

[90MarkVII]

Thank you.

[TX_Snake]

Make sure when you change plugs the eng is hot. It sucks, but with a hot eng you are less likely to break the plugs in the head.

[90MarkVII]

My son (in Denver) is going to buy (don't recall the year) an F150 and I knew there had been some issues.
Current owner had them swapped prior to issues manifesting.
Thanks anyways, guys.

[jetboat]

Make sure when you change plugs the eng is hot. It sucks, but with a hot eng you are less likely to break the plugs in the head.

not on a 2 valve