Due to age and possible damage during removal, it is recommended to replace the spark plug boots when replacing the spark plugs,Google+
Car Problem Reports
Lincoln Aviator Replace Spark Plug Boots When Replacing Spark Plugs
Lincoln Aviator Problem
Visitor, 2003 Lincoln Aviator
Had OBD message that I had 3 bad coils (which each were giving off bad ODB codes).
Looked into replacing new plugs (Pre-Gapped) & new coils.
Ford wanted between $65 & $120 per coil.. all 8 of them????
I checked around online & found a full set of 8 Brand new OEM coils / boots for $145 the lot.
Got them from the same place that Ford gets theirs... 8 for the $125 ford would have made me pay for just 1 GRRR