Ford F-150 Heritage Problem Report
Ford F-150 Heritage One or More Spark Plugs May be Ejectioned From the Cylinder Head
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.