There is a technical service bulletin for the V8 engines regarding a possible problem with the spark plug being ejected from the cylinder head, damaging the threads in the spark plug hole. If the vehicle is under warranty, cylinder head replacement is recommended. If the vehicle is out of warranty, Ford authorized the use of a specific thread insert to repair the head.
Car Problem Reports
Ford F-150 TSB For Possible Ejection of Spark Plug From Cylinder Head
Ford F-150 Problem
Engines Affected: 4.6L V8, 4.9L 6 Cylinder, 5.4L V8, V8
Average Mileage: 145,411 mi (90,000 mi - 238,890 mi)
Visitor, 1999 Ford F-150, 5.4L V8, 118,000 mi
The plugs were replaced with Helio coils, new threaded sleeves in the head. Two have ejected. It is limited to the rear on both sides of the heads. Relatively easy fix, if it happens to one, get all 4 rear ones done to save labor. Should be good to go.
Visitor, 1997 Ford F-150, 4.6L V8, 150,000 mi
Finally blew out the #4 plug. Head damaged bad enough where inserts were not an option. Replace the heads with 150k on the lower end??? Nope. Total cost of one blown plug is about 6K.
Visitor, 2000 Ford F-150, 5.4L V8, 90,000 mi
Three of the eight have ejected. Now carry plug, coil and tap every where I go. Now can change out in under 30 minutes.
Visitor, 2002 Ford F-150, 5.4L V8, 170,000 mi
I have had three spark plugs eject over the last two years or so and the number 2 plug just ejected again and my mechanic says I need to replace the head because the aluminum melted around the threaded hole and he can't fix it again with a helicoil.
Visitor, 2001 Ford F-150, 4.6L V8, 94,000 mi
3000 miles after a tune up the number 3 cylinder ejected a spark plug a couple of thousand miles later the number 5 clyinder ejected a spark plug.
I am now in the market for a Tundra or a Ram 1500 or a Silverado.
Visitor, 1991 Ford F-150, 238,890 mi
I have now replaced 3 blown out plugs 5.4 ltr with helio coils.FORD should Step up to the Plate and Help pay for new heads or have them machine new heads with new threads to eliminate this problem.This Truck has been fabulous to this point. I hate to have to change my Brand of truck for the next purchase. Roger Corbiere
Visitor, 2002 Ford F-150, 4.6L V8, 165,000 mi
cylinders #2 and #7 blew out on seperate times. i had to have it tapped and use a steel sleeve. mech. said not enough threads on the head. around $400.00
Visitor, 1999 Ford F-150, 137,400 mi
#2 plug blow out problem on 5.4 in my 99 f1504x4
Visitor, 1991 Ford F-150, 4.9L 6 Cylinder
new spark plug