My truck is a 03 Supercrew FX4 w/ a 4.6, and it appears to missfire after I go mudding with my friends.

Now bear in mind that my friends and I do more splashing around than serious "4WD only" type mudding.

I seems to pickup some mud/water down in the spark plug hole and it causes my truck to misfire. Most likely, blocking coil pack from properly sparking the spark plug.

It seems the COP rubber boot does a terrible job from stopping foreign matter from getting down there.

Granted, I did have the whole Spark Plug stripping threads issues a while back ago, but have sense had a professional heli-coil the plug in there. Reason I tell this, I still have not replaced the Coil Pack and it does not attach to the one bolt mounting spot and there for bounces around as far as the fuel rail allows it to. (I hope that made sense to ya'll, if you have had the spark plug thread issue it should have)

So my question is this; Is there any way, either aftermarket or 'custom', to prevent dirt, mud, and/or water from getting between the spark plug and coil pack and causing these damn missfires?

Thanks F150 Forum in advance,
Chris

 

My truck isn't that new so I don't know what the COP looks like, but if it's still like a spark plug boot then you can put dielectric grease in the boot and plug it back in. That's the stuff they always try to sell you when you buy new plug wires. Don't get the little packets though, get a tube and do them all.

 

Was wondering why the COP doesn't bolt down. If the bolt broke, you should be able to drill it out and install Heli-coil. FYI, they come in all sizes and thread pitch.

 

Just haven't got around to buying a new coil pack, but as long as it is making contact it should fire.

And the bolt did only broke on one cylinder but the little plastic arm that connects the Coil Pack to the bolt hole, broke off when the compression was pushing the spark plug out.

 

The Coil Over Plug style was first on only 5.4s and then later 4.6s got it. It is basically the Coil Pack and spark plug wire combined into one piece per cylinder. It looks like a coil pack with a spark plug boot hanging off the bottom and has a plastic arm off the top side that is used to bolt it down, so it doesn't move around while driving.

 

So I removed the COP and anything else that was in my way of seeing the sparkplug hole clearly (i.e. intake, power steering fluid reservoir, etc.) and found wet mud on the bottom of the COP (no surprise) then I tried to clean out the plug hole as best I could with a rag and my over sized hands. Then I pulled the spark plug (carefully as to not upset the easily angered plug threads) when I got the plug out it was covered in mud (again no surprise) I cleaned the COP and Plug to get all the wet mud off. But I knew the spark plug would just get dirty agian since the hole probaley had a bunch of mud in it. I needed something to absorb the mud and had a a way to control it in the spark plug hole. Then I got an idea (your gonna love this)! I went inside and stole on of my wife's tampons!?! LOL I knew it would suck up all the liquid mud still in the saprk plug hole and had a string on it that I could easily pull out.
So I put the cotton missle in the spark plug hole and used a socket extension to push it down and pulled the string to raise it up, I repeated this process a few times and then would rinse the "rag" out, and do it all over again, until it came out clean. Then I reasembled everything and fired the truck up. no more miss!
I can't believe the ideas I get!?!?

But this still leaves my original question, How to I stop mud/dirt from getting down there in the first place??

 

put gasket seal around the spark plug. it will be a B!$@# to get the plug out but should work. the real question is why isn't the plug sealing it's self when seated.
you may have a bigger problum then just the mud.

 

Plug seals and tightens down fine, it is the fact that ford design the area under the fuel rail (where the spark plugs live) like a giant funnel to catch all water. The water does not enter the motor just makes the coil packs have bad connection with the spark plug and tahdah, dead cylinder!

 

Silicone around the spark plug hole will seal it. I have done this to many off road trucks with great success. Even ones that have just plug wires a little silicone on the porcelin of the spark plug works wonders.

 

soak dn with WD-40