I've had quite a bit of experience changing COP's in the last couple of years. My 4.6L '03 Screw (130k mi.) has gone thru about 5 of them. Also replaced the original plugs about 5k back. However, I have a problem that now appears to be something other than plugs or COP.

I have replaced #1 cylinder more than others, and until last time had used AZ as source. With the last one, I went with Motorcraft after reading posts here that advocated OEM.

I am getting a cold-start misfire that throws the #1 cylinder misfire code, but the new COP is obviously not the culprit (and quite possibly, neither was the one I got from AZ). The misfire lasts for maybe 3-4 minutes as the engine is warming up. However, I wouldn't say it gets to normal operating temp before the misfire subsides. The code has actually cleared itself (the light on the dash is no longer illuminating) although I imagine it would still be in memory if I went back to AZ and had them read codes.

From what I've read in other threads, this sounds like something is possibly leaking into the cylinder itself causing it to run rough temporarily until all of "whatever" is burned off. I have pulled the plug and don't see what looks like abnormal carbon buildup from burning oil, although I am seeing loss of oil between changes that must be getting burned because it's not leaking externally. I don't see any loss of coolant, so don't think it's water getting in. Cannot see any other reasonable explanation, but I'm posting in hopes someone might be able to direct me to other possible causes. At this point, it's just a nuisance but I'm afraid that this could escalate to something more serious.

Thanks in advance for your help.

 

Just a thought: What about replacing the COP before and/or after the #1 in the firing order. Electrically I could see one of them causing an issue. Hopefully someone else can either confirm or lead you another route.

 

There is an issue that your not addressing with the boot and possibly moisture is getting in and causing the way it acts.
Remove the plug, blow out the well with compressed air and clean it dry with a rag.
Use a new boot, grease up the inside of it's tip with dielectric and be sure the spring has not hung up inside to boot.
Your coolant level does not have to go down for this to be an issue.
Only a little bit trapped in and it cannot get out. Etholyne Glycol does not evaporate after the water goes.
When the CEL is not on, a reader or scanner looking just for code won't see any.
The user must know about mode 6, test 53 that shows all cylinders missfire counts and detects which cylinders are likely to cause an issue at some later date from the missfire counts, by common logic.
Otherwise your missing a lot of info and so the hassle goes on.
Good luck.

 

Thanks for the tips. To clarify, I should say that the code reader AZ uses seems very low-budget, and I think it only puts out the code number. They're looking at it and say "cylinder 1 misfire".

Here is a picture of the spark plug well with the COP out. There is a slight hint of staining beginning about an eighth of an inch down. Can't get the camera right over the hole and still shine a light down in it. The flash doesn't work either. It looks like this all the way to the bottom.



The plug doesn't look abnormal in any way. Here are a couple of pictures.


Residual dielectric grease on the electrode.


Tip doesn't show any signs of carbon buildup.



I didn't even take a picture of the COP because it looks like it just came out of the box.

After removing the COP and plug, I cleaned the plug electrode and reinstalled it. I disconnected the fuel injector and started the engine briefly, to see if in the cold state it was leaking anything into the spark plug well. I could not see anything. I shut it down, greased up the COP spring and connector prongs, then put it all back together.

Considering taking it to a legitimate shop (vs. AutoZone) to see if they can do a more complete diagnostic. It had been less predictable until lately, but now it does it almost every morning and anytime it's been sitting idle for 5-6 hours.

Still hoping someone might be able to tell me they had this exact problem and how they resolved it.

 

Great pictures. Love the macro shots. Pictures really are worth a thousand words.

Something that is often misinterpreted is the use of and purpose of dielectric grease. It is a moisture blocking NON-conductive grease. Meaning that it will block electricity if applied to thick. Your spark plug tip looks pretty thick and I could see that causing problems, especially if you spring is not putting enough pressure on the tip of the plug.

Bluegrass is right (again) on the moisture in the spark plug well. You can see it on the threads of your plug. The boot does not appear to be sealing very good.

If you want grease to put on the end of the spring and/or on the tip then you should use a conductive grease like OxGard. http://www.olypen.com/craigh/oxgard.htm

 

The plug and well have to be absolutly dry at all times.
The boot has to be good or new.
Only apply enough grease to the tip ] and first 1/4" of the inside so the boot
'finds' the plug tip when you set the coil in place.
The grease does not have to coat or cover the plug tip.
This part of the job is very critical for missfire prevention.
The plug does not look real good.
Look on the top of the head around the well opening.
If there is signs of anyting fluid find the cause or this will keep happening.
This is all there is to it!
Good luck.

 

bluegrass have a ? i'm misfiring on 2 and 3 coils are good running lean what else could it be ?

 

Things are getting streched out.
Begin again with what you now have for codes so a new approch can be done.

 

I took it to the shop guy didn't give me a code said that cy. 2&3 misfiring coil are still good it is a 2003 ford expedition 5.4 l

 

He won't get to it till Monday but if I can fig it out then ill fix it myself

 

Bumping this thread - don't know what happened to my Photobucket pics up there...

Took the truck to a shop and they flushed the injectors, then swapped the plug and coil between two cylinders, told me to drive it and see if the code popped again. Sure enough, still getting the #1 cylinder misfire. They said it's likely either the fuel injector leaking down or a valve problem. Would seem most likely to be the injector. Anyone have a link to the "how to" on replacing the fuel injectors? Have been looking around but haven't seen anything. A link to the FSM with the procedure would be great.

Thanks!

 

Apparently I rearranged my pictures in Photobucket after that post... here's the two that got moved:

 

Replaced the injector on #1 cylinder yesterday, drove it and seems to run fine. Let it sit overnight, and when starting today seemed to still have the misfire. Reset the codes, so it will take a while for the SES light to come on. But I'm almost positive it is still missing, and most likely from the same cylinder.

In hindsight, I wonder if I could have proven the leak-down theory by running the engine with the fuel pump fuse pulled, just to deplete the fuel pressure before letting it sit overnight. This seems like it would be feasible, but I haven't tried it with the new injector.

Here's a picture of the new (left) and old (right) ... Motorcraft changed the color? Seems like an odd thing to do... just assuming O'Reilly gave me the correct part.



Open to any other thoughts. I am not sure how to test the COP or FI wiring, but it wouldn't seem likely that they would have a fault for only a few minutes, then run flawlessly after that. Comes back to the possibility of something leaking into the cylinder (either fuel or water)... not likely I'm going to go any further than this with the diagnosis, just hoping someone out there can point out something I've missed.

 

After running a week on the new injector, about 130 miles, that's definitely not the problem. SES light has come back on, as expected. I pulled the fuse and cranked the engine to deplete fuel pressure, then started it the next morning and found that it still runs rough (as expected).

So it's not the COP, it's not the FI, it's not the plug... there's wire connecting all of those things to the rest of the truck, but it looks to be in good condition. Would love to know if there are any other "links in the chain" that I could test. Don't really feel like having the engine torn apart on one mechanic's theory that it's a valve problem.

Some feedback, please...

 

Should have mentioned that I've looked it over good for any signs of moisture, and it is bone dry (at least on the outside of the cylinder). The grease is light on the electrical connections as well, just enough to lubricate. Really at a loss as to how this isn't an electrical problem of some kind, but don't know other parts to check. What other diagnostic tricks can I use to look for other causes? Any way to vacuum the cylinder out after it's sat and see if there are any liquids in it (i.e. water or oil)? Figure by pulling the plug and fishing a small piece of tubing down into the cylinder I might be able to get something, but that's a long shot.