2002 ford explorer misfire

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2002 ford explorer 4.0l 140K P0302 and P0316. engine shaking. Light came on few days ago and wife drove home 5 miles with it misfiring. Before that no rattles and smooth. Oil level appears to be higher than normal, maybe fuel is in it. (still caramel color)

Removed all APP103 double platinum spark plugs and number 2 had one of the 2 platinum disc burnt off on the spark plug side electrode, while all other were in tip top shape.
Replaced all of them with copper cores 103 and get the same shake and error codes. Order coil pack and wireset today. How does 1 plug melt one all the others look good? Were did the Platinum tip go?
Any advise welcomed.


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It seems like Autolite and Champion don't laser weld the Pt disc on their plugs - they look different compared to a NGK/Denso or Bosch OE finewire plug which is a Pt/Ir "nib" laser welded onto the base Ni/Cu center electrode.

If that engine still throws a misfire code after the new coil pack and wires, you might have bigger things on your hands. Try the wires first - cheap and they do go bad. Coils almost always never fail(but they still can).
 
Pull the coil and and inspect for cracks. Look over every square inch - they can be really fine little buggers.

As for the plug - it seems to happen for often to Autolite and Champs as was already pointed out. Seen it several times.
 
I would think if the coil was bad, you'd have a misfire on 2 cylinders, since this is a waste spark system. I would've definitely tested the coil before buying a new one, super easy to do with a test light and only takes a minute. If it's still misfiring after the new wires and coil, I'd do a compression test next.
 
Originally Posted by exranger06
I would think if the coil was bad, you'd have a misfire on 2 cylinders, since this is a waste spark system. I would've definitely tested the coil before buying a new one, super easy to do with a test light and only takes a minute. If it's still misfiring after the new wires and coil, I'd do a compression test next.

You'd think that, but it doesn't always work out like that.
 
Wet coil and wires down w/ water and look for leakage. We have bad wires quite often on our fleet of 2001 4.0liter fords and more recently are being hit with a lot of bad coils that were original ford parts from 01.
 
Originally Posted by The_Eric
Originally Posted by exranger06
I would think if the coil was bad, you'd have a misfire on 2 cylinders, since this is a waste spark system. I would've definitely tested the coil before buying a new one, super easy to do with a test light and only takes a minute. If it's still misfiring after the new wires and coil, I'd do a compression test next.

You'd think that, but it doesn't always work out like that.


Yeah but it usually does. I'd hook up a scan tool capable of live data and look at everything w/engine running, and clear the prior codes to see what pops up next... except this is premature since new wires and a coil pack were ordered, if the existing were factory then these might as well be tried. At least the coil packs (and wires) on these are relatively inexpensive if you buy online and don't splurge on Motorcraft.
 
I placed an old working plug into the wire on number 2 while using jumper cable to ground it and cranked it and got no spark. Placed the setup plug directly into number 2 output on the coil pack and no spark.
Amazon arrived with new coil pack and wire set few hours ago and she is back up and running good. I tested the resistance on the cables and all around 10K which is fine. But it was time to do it.
I have to wonder which was the cause (went first) the spark plug destructing or the coil pack?



buddylpal: You can clearly see in all picture provided one plug has a very visible circle (grey in color) on the electrode which is the platinum disc and the other one is gone and electrode is etched.
 
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