When I looked the plugs on the 4.7, I was a little confused about the whole wiring bit and stayed away from buying any new plugs for a while.

 

Well I just downloaded the service manual and checked the spark plug gap again, looks like the dealer was right. The service manual calls for .042" gap for the 3.7L and a .040" gap for the 4.7L. I'm not exactly sure one way or another exactly how critical the gap is being that the spark plug gapping tools are not going to accurately get you to thousandths of an inch, it seems to me like its more of a close enough game, I guess I'll find out soon!

 

The service manual I had said .35in... are you sure it said .42 for a 3.7L??

Dakota Stone... what wiring are you refering to about the spark plugs....??

 

I downloaded the service manual in the forum and that's what it says to do, the ignition system is on pgs 1030-1050 there it tells you how much to gap the plugs, what to torque them at and how to remove the ignition coils to get to the plugs.

 

I think all the confusion is coming from this part that shows the gap tool and a plug being gapped at 0.35:

sparkplug.jpg

But, the actual specs are:

gapSpecs.jpg

 

Installed my 3923s 2 weeks ago at the recommended .035 in my '05 3.7. Keep in mind it is a colder range plug. The stock hot plugs were supposed to be .040. None of the stock (factory) plugs were properly gapped. Ranged from .043 to .045. Much smoother idle. No need to worry.

 

I don't know about the 3.7L, but the 4.7 doesn't have a distributor cap and it also doesn't have the normal wiring at the top of the plugs. I guess, and I'm sure someone will correct me, but each plug has some sort of separate distributor. I'm afraid to take one off without hurting it.

If you look at the picture, look at where the valve covers are, it's not the best pic, but you should be able to see what I'm talking about.

[IMG]local://upfiles/19913/555A2B0AA82242BC9043FF6573DE0D75.jpg[/IMG]

 

I would go by the sticker thats on the underside of the hood for the proper spark plug gap.

 

Direct Ignition

Each plug has it's own coil over it. The computer tells it when to fire.

 

Stone, our trucks use coil-packs on the plugs, there's a detailed step by step for removal and changing the plugs in the service manual.