I have a 2001 F150 4WD Lariat 5.4 liter and I am having problems every time it rains hard with moisture getting to the spark plugs. It started with #1 and #2 so I replaced the coil packs and thought it would fix it but it didn't. Yesterday #8 had moisture in it. Can someone please help me? What good is a 4WD if you can't get it wet?

 

Use diaelectric grease on all your high tension connections(plug boots,coil packs(or cops),etc. This keeps moisture from migrating to the connections. If you go thru a lot of water,you might want to check all your electrical connectors to ensure the connector seals are intact.