Completely Blown Away
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Joined: Apr 2018
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From: Hamilton, Ohio
Completely Blown Away
I'd like to start with a big thank you gents for the post s that I've read so far, they are all helpful. So I'm not asking the same questions here's some background.
4.6 in a Expedition AWD, I did a complete tune-up (plugs, wires, coil packs, etc.) Now for the past couple weeks cylinder #7 is constantly fouling the plug. In the beginning it was blowing off the wire(fixed), now its the new plugs. When I pull the plug, half of it looks new and the other is burnt. Now when I'm tightening it down it feels like I'm only threading two sides of the plug.
It's like all the other post that I've read. Good power for a few days then it falls on its ***, missing, no power, no acceleration but idles OK.
So my questions are has anyone had troubles with threading of the plugs? Cause the hole feels like it's egg shaped. And when I was changing plugs and wires, I found that someone had placed a screw between the wire and the plug. Now I've never come across this before, so is this so kind of trick or something for good spark? Because it was on cylinder #7.
4.6 in a Expedition AWD, I did a complete tune-up (plugs, wires, coil packs, etc.) Now for the past couple weeks cylinder #7 is constantly fouling the plug. In the beginning it was blowing off the wire(fixed), now its the new plugs. When I pull the plug, half of it looks new and the other is burnt. Now when I'm tightening it down it feels like I'm only threading two sides of the plug.
It's like all the other post that I've read. Good power for a few days then it falls on its ***, missing, no power, no acceleration but idles OK.
So my questions are has anyone had troubles with threading of the plugs? Cause the hole feels like it's egg shaped. And when I was changing plugs and wires, I found that someone had placed a screw between the wire and the plug. Now I've never come across this before, so is this so kind of trick or something for good spark? Because it was on cylinder #7.
Cross-Country
Joined: Jan 2016
Posts: 79
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From: SoCal
I had a 98 f150 4.6 that was having the same issue with number 7. What was happening is that the plug threads were starting to go bad. They would let some of the compression leak into the spark plug tube. Due to the fact that on that motor it uses a wire with a boot that does a pretty good job of sealing the top of thr spark plug tube, the leaking compression would pop the spark plug wire up out of the hole about a half an inch in order to relieve the pressure that was building up inside. When it did that, the truck would develop a misfire, but as soon as you push the wire back down, itdd stop until it popped it up again, usually when i was going up a grade or making the engine work harder. The previous owner probably used the screw as a way to have the plug wire slightly popped up out of the hole allowing it to vent the leaking compression, but at the same time let the spark travel thru the screw to the top of the plug.
My buddy at the machine shop tapped the spark pkug hole and put an insert in it, and it ran great until i sold it.
My buddy at the machine shop tapped the spark pkug hole and put an insert in it, and it ran great until i sold it.
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DarrellJ
1967 - 1972 F-100 & Larger F-Series Trucks
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Dec 23, 2010 02:42 PM
