This may be your problem too.

MartianBob

Registered User
My car started running like crap, getting worse over a three week period. It was dogging at low rpms under very light throttle. Felt like a TPS or MAF problem. Then degraded into classic sc misfire symptoms: stumbling/bucking under load and heavy throttle at all rpms.

I swapped out a bunch of spare sensors to no avail (we all have them by now right?). I had replaced the plugs/wires about 2 months ago, so I though they were good (they had been good for the first month).

I started the car up in the dark 2 nights ago. Two of the wires looked like X-mas lights. I tried swapping in some of my old wires and no-go.

So I bought another motorcraft set yesterday. Swapped out the two bad wires, and the new ones were arcing too. Wtf?

After numerous wire swapping permutations, I pulled one of the plugs on a bad wire. The plug looked Great! Under bright light and close examination the plug still looked Great. No crackes, etc. that I can see.

I swapped in old plugs on the two pesky wires, and all wire arcing and misfire was solved.

I don't know what is wrong with these plugs or exactly how they turn a good wire to crap But... They did. Of course the wire did recover.

I could have saved myself some serious time and frustration by looking at her in total darkness sooner.

Oh yea, I've performed my share of plug/wire swaps on these cars; and I'm damn gentle and carefull - no swivels or extensions in my technique. I don't even think bad thoughts about them for fear of retaliation.

Good luck, I hope this helps someone out there.
Cheers
Bob
 
Very interesting. My first question is what brand and type of plugs did you use? For some reason those two plugs developed very high resistance causing the energy to go to path of least resistance.
 
2 things:

Did you use die electric grease and was the tip of the plug (plug wire end) screwed on tight?

Jeff
 
details.

The plugs are Autolite APP-103. The little platinum spots looked ok. And I've used them before with happy results.

I use dialectric grease, and try to put it on the ceramic portion of the plug only - but it aint a perfect world.

The screw tips were secure.
 
I've experienced the same thing and, it was a hair crack in the ceramic portion of the plug. Did you use a magnifying glass and some graphite dust (that's what I had to do to find the ones that were cracked). What a PITA. In my case it was my own fault, as I used a plug socket that had lost it's rubber ring/washer - so I must have tilted the socket enough to stress the plug. Now I make sure I use a piece of scrap rubber hose to get the plugs fully seated and then use the plug socket with a palm ratchet - so I can get it as straight as I can.
 
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