gone postal

Why 6 COPs on a V-8? Call it curiosity.

Bwkemp

I think I may have it figured out! I finally took the new spark plug out of #6 and put it in #5 and the miss moved to #6. I tried different coils and the two used plugs that I removed that were still usable and none of them make it run.

I am hoping the new plug is bad, and the two used ones are bad (I'm thinking maybe they cracked inside when pulling out). They all do spark with an alligator clip on them, but maybe not enough?

I'm ordering a new one and try that...

Gone postal I just mistyped it should had said 8 instead of 6

gone postal

Makes more sense now. LOL

Plugs have a higher infant mortality rate than they used to, like everything else, they're better in some ways, worse in others.

Bwkemp

I'm going to be out of town for a couple of days but will post back as soon as I get a new plug and make sure that is it. I moved it to another cylinder and now it is dead so I'm 99 percent sure it is the plug. The new plug that works sparks just the same as the one that doesn't work and the two used ones. Using a large alligator clip grounding them. But who knows what it looks like in the hole.

I could see how the used ones would have stress cracks from pulling the tips out (most of them broke In two)

I also did a compression check on two cylinders before I figured it out and they were okay.

Cheers and I hope my struggle helps the next guy!

gone postal

This is actually an excellent reminder of how touchy the plugs can be. was reading and completely forgot about the issues people have had with replacement plugs.

One of the nice things about my 4.6L LOL

Bwkemp

The new plug fixed it! I think it fixed the original problem of misfire at 40-50 mph too, But I will post back if it didnt. (it wasn't warmed up all the way when checking that).

redfishtd

SP515s have a high failure rate right out of the box. The newest plug is the sp546 that has been quietly introduced by ford with no information .It looks like they changed the attachment of the plug snout as they no longer have the funny blue weld marks there.
Add to that that the carbon breaking your plugs on the way out is still there breaking some plugs on installation .It is recommended to clean that area out with carb cleaner.