Mueller, I was always able to find the bad one by comparing readings on an ohm meter. I don't know what value I got but, I replaced the one with a value that was way off compared to the others. For me it was easier to remove them and test them on a bech. It fixed it for me. Autozone now stocks them, if you shop aroung you can get a good deal. If I remember I had Autozone match checkers price of $35-40.
First, get the codes pulled to see which one is flaking out. The easiest way without being able to do a power balance or coil stress test would be to simply walk that bad coil around to a cylinder that isn't misfiring to see if the misfire follows that coil. Just because an ignition coil checks okay resistance wise doesn't mean that it'll hold up under load.
What if you don't get a code? I don't have that bad of a running problem, but at times a rought idle when cold, or it might take a couple cranks to fire up(happens about 3 out 10 times) I had changed plugs, boots, IAC, cleaned the TB. No codes, changed programs with my programer, changed fuel filters. I did notice that the blades on a couple of the coils had a slight greenish glaze.
Im getting ready to check the COP's tonight...Autozone said my code was P0355 Ignition Coil Primary circuit malfunction which really doesn't tell me a whole lot....any suggestions on which one...or if it is a COP problem at all?
Does anyone know if there is a TSB on the COP's and where to find a free copy?
I have an 01 SCrew 5.4 and had one go bad at about 20k - dealer misdiagnosed first and got it right the second time. Recently at 78k I had another go bad while on a trip - limped into a dealer who took me for $400 to replace another COP. Now I have the early symptoms of another going bad.
Is this a horrible design? Should Ford replace for free? Just upset and wondering...
I really want to get +150k out of this truck, but don't really have the time to mess with this issue every few weeks!
Are they easy to replace once the culprit is identified?
You are right...I gave up on 7 and 8...4 is bearable...Did you have to take off the fuel rails for 7 and 8?????
Oh...all of my coils look the same except for two of them...those two have a green motorcraft sticker on them...the rest are black. I am wondering which are the replacements and which could be factory?????
By the way, I switched around the 5 and 6 to see if it would throw a different error and no...it did not...so I now think that the coils are not the problem...and they checked out ok on the OHM test...
I'm stuck now and looking for a good place to take the truck...in Ohio...
Hmmm...the original codes were for the two cylinders with the green stickers on them....perhaps I should swap those for new ones even though the ohm test checked out???....then take it to a shop if that does not cure it.................
If you purchase a Haynes book it will tell you how to test the COP with an ohm meter. I noticed with my old truck 2000 F-150 w/ 5.4 it did not like anything but the motorcraft plugs that came w/ it originally. I also know O'Reilly's has a COP by borg-warner that carries a lifetime warr. Good luck
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