spark plug and coil on plug questions 03

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dirtrider

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I have an 03 expedition with 60K miles. It is throwing code P0302 so the number 2 cylinder is misfiring. I am thinking it is just the coil on plug. Since I'm replacing that I figured I might as well do my spark plugs now too. Some questions concerning that process.

1. Do you agree it is probably the COP? What else could it be if not that? Do those COPs tend to go out with regular frequency or do they tend to last a lot longer than my 60K miles worth?

2. I plan to change all 8 cops and 8 plugs while in there. Planning to use oem motorcraft cops and autolite APP103 plugs. Any issue with the APP103 plugs? I have seen some say these come off the same line as the motorcraft ones. The issue I am more concerned about is if the metal at the threads and any finish on them is the same as the motorcraft ones??? This is to eliminate any dissimilar metal issues and links up with my next question.

3. Should I use any anti sieze on the plug threads? I am concerned about two things. One, is there any dissimilar metal issue between the plug threads and aluminum head that necessitates this? Secondly, how does this influence my torquing of the plugs?

4. What torque should I use for the plugs? I have seen 13 ft lbs. What about with any anti sieze?

5. What about grease on the plug boots? I have never worked on a vehicle with coil on plug design. Do the new boots come with grease and or should these boots be greased inside and should there be grease put on the plug porcelain as well? Any particular grease recommended?

6. What temp should the engine be when changing plugs? I was planning to do it warm to the touch but I've seen others recommend hot or cold.

7. Does the 03 expedition have the lower count of aluminum threads on the heads or was it revised by this point. Some are saying like only 4 threads but I've seen other posts saying it was revised and fixed by this time. Of course there is the whole other issue of plugs sticking and breaking off on the newer 3 valve engine. Not sure which is worse!

8. Is it bad for me to drive it like this at all before my parts come in? Just 6 miles to work and back for a few days? I actually already did yesterday and today. The car still runs but just not smoothly. I wasn't sure if the injectors keep spraying fuel in the cylinder and if it doesn't ignite if there is any risk of hydrolock or anything. Dumb question perhaps but I don't know the ins and outs of how everything works and figured I'd ask. Cars are not my forte but I'm not afraid to turn a wrench.

If you have any other feedback or links to good write ups on this procedure please post those as well.

Thanks!
 
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dirtrider

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I found a couple interesting faqs on Blownoutsparkplug.com that have some relevant advice.

Q: Why do you prefer 28-32 foot lbs torque instead of the factory specification?
A: Over the past few years we have heard from many of our customers that they tightened their plugs to the correct torque but they still came loose. We worked with 10 other Ford Certified Master Mechanics and concluded that 28 foot lbs of torque would be satisfactory. We have been using 28 foot lbs of torque for many years and have never had one come loose or strip out. To verify that we would not damage the original threads we used a test cylinder head with good factory threads we applied over 100 foot lbs of torque to the spark plug without any failure.

Q: Do you use Anti-Seize when you install new spark plugs?
A: No, we always use Motorcraft nickel plated spark plugs to stop any issues with electrolysis.

Q: Have the threads in the newer engines been upgraded?
A: Yes. most all 1997 to 2003 4.6L, 5.4L, 6.8L engines used the 4-5 thread design cylinder head. In late 2003 the SOHC 2 valve type engines were upgraded to a 8-10 thread spark plug design. The newer 3 valve type engines use a whole new type of sleeved spark plug.
 
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dirtrider

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more findings per my questions above...

It does seem that the preference is to not have any anti sieze on the plug threads at all. The autolite app103 seems to be nickel plated so as to not require anti sieze for corrosion control.

I disconnected my #2 coil and fuel injector wire connectors. I think it is safe to drive this way for the short term. From what I read the cylinder order is from the front passenger front 1,2,3,4 and then on the drivers side front 5,6,7,8. So I disconnected coil and injector on the second from the front on the passenger side. Hope I got that right...
 
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blacksunbird

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Also, ensure that the connector for the COP is firmly attached...I talked with a mechanic who is familiar with Ford Mod engines...he communicated that the connector for the COP is a somewhat crappy design, with a reputation for breaking easily and vibrating loose from the COP, causing a misfire and the DTC 0302 code being thrown.
 

blacksunbird

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when doing the tune-up, use dielectric grease for these connectors...I am using a jack-leg method for securing the connector to the COP...wrap the connector (which by this time is connected to the COP, I assume) in electrical tape to keep the connection together...works for me.
 

05expedeb

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In reading this thread may I suggest that you change the spark plug boot and coil wire inside of the boot. My opinion is that the boot may fail rather then the coil. AGAIN THAT IS MY OPINION. Also use dielect greese on the coil wire inside of the boot.

If you do change the coils they should come with new boots already on them.

In the 4 expedions that I have owned I have never had to replace a coil but I have had one boot blow a pin sized hole in it which gave a code of 0304 which was solved by replacing just the boot.

I am not saying that this is always the case but it is something to keep in mind. Also the boots are much cheaper than coils.
 

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