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I have a 2001 Ford F-150 Supercrew 4x4 with a 4.6L engine.  It has had misfire problems four times in the seven years I have owned it.  Mechanics have changed coil packs and/or plugs and the problem has gone away, but it always comes back.  Most recently, when I had a mechanic look at it, he found that there was a significant amount of oil in and around the coil packs.  He took them out, cleaned them with brake cleaner, I believe, installed new plugs, and replaced the coil packs.  The truck ran great for two days, then started misfiring again.  I'm going to get into it in a couple days and I suspect I'm going to find oil in the packs again.  (I am aware that my truck has used oil over the last year or so.)

Where is this oil coming from?

If I check it out and DO NOT find oil this time, what is the cause of the misfire?  

one thing i have found handy..... having an air nozzle with an extended tip... or a piece of tubing... so you can pull the coil packs...   spray some brake cleaner in...  insert the air nozzle... cover with a big thick towel... and apply the air... this blows all the oil out of the hole...

i would think that you might want to check your PCV system...  make sure that you have a ford or motorcraft PCV valve in it.. some of the normal brands are sorted by shape not flow.. so who knows what you will get..   to big it burns oil...  too small it blows gaskets...

i don't know if the 4.6 motors have it.. but ford used a filter under the PCV in 5.0 and 5.8 EFI motors... over the years oil would build up in it.. harden and block the airflow from the crankcase into the PCV system...  so the PCV valve would work.. but the passage was blocked by the clogged filter...


do you see any leaks form the valve cover gaskets????

by the way.. using dielectric silicone tune up grease to lube the boots were they seal against the coil... and on the inside of the boots where they go over the spark plug insulators.. wipe it in. so it only gets on the sides.. you don't want it on the contact of the plug...

this prevents the high voltage from leaking down and out from under the boots..  and has cured a lot of misfire ills..  

I do not see oil leaking from the valve cover gaskets, but I am going to clean it with Gunk today or tomorrow and take another look.  I just can't figure where this oil is coming from.

I will try the dialectric grease.  

Hello,

Did you find the source of the oil leak? I have a 2002 explorer with the MOD 4.6 V8 2 valve. There is oil leaking into the spark plug tubes and causing the plugs to ground out. I can find the source, it does not appear to be from the valve covers. I have read on another forum that oil is leaking through the spark plug tube wall through the casting because it is porous. Did you find the source of the leak and have oyu been able to fix it?

Thanks