I have replaced a few of the COP on this truck. 140k miles and the #4 coil keeps throwing a code. Was headed through the mountains and the CEL started flashing and I had no power. I have replaced the #4 coil pack twice now and today it showed #4 and #5 misfire. Replaced the #5 and ran smooth for about an hour. P0304 #4 cylinder again!!! Not too sure what the issue could be now? Not showing any other misfires but took three weeks to show the #5 going bad. Any help!!

 

I have replaced the #1,3,4,5,6 COP on this truck to date. New plugs last year. Only broke one of the eight and had the extractor tool...

 

The usual question from this forum is what brand of COP are you buying?

 

I have purchased the motorcraft and the BWG from Oriley's. Same issue with either.

 

I am thinking of changing the #4 plug next along with the rest of the COP's.

 

Pulled the #4 plug out and it was completely destroyed. Still have a bit of s shudder like I have another ciol pack going bad.


Two year old plug.

 

so I'm going through coil pack issues now. I had a misfire in cylinder 7, ended up finding a good set of packs and replaced 1-3 and 2-7 basically because 4 and 8 aren't easy to get to for me. I changed them last night, it felt weird on the initial post change drive but then cleared up quick. Got in it this morning to head to base and check engine light was on and it definitely felt off, worse than before. I've got 147k miles on it, should I have changed spark plugs too? Its a 2005 5.4L, I've only owned in for 3 years so in my time of owning it I haven't changed the plugs.

 

What codes do you get? Your local parts store should be able to pull them for you.
With the codes they may point you right at your problem. Maybe the two cylinders you didn't change? Maybe not.
Changing the plugs wouldn't hurt either, but you should change them ALL, same with the coils (since you must have them)

 

I would for sure look at a plug change. You shouldn't need to change all of the COP unless it goes bad. I changed my plugs at 120k and I only broke one. I removed the COP and sprayed Deep Creep into each of the plug holes and let them sit for 20 minutes. Make sure to go to your local parts store as most of them will rent the removal tool if you happen to break one.

 

I have found my problem. The threads are screwed up on the #4 cylinder. I am going to get the ATD kit $220 from Amazon and rethread the head. I will post pics and a how to since it is hard to find any.

 

The only inserts that will last are Timesert.

http://www.timesert.com/html/triton_repair-3valve.html