Carbon? in spark plug tubes # 2 & 3

[zanglezonker]

I just pulled the plugs on my 94 5S-FE, and the number 2 and 3 wire leads show brownish carbon fouling.
http://www.flickr.com/photos/23132658@N03/2217514272/

The plugs themselves show carbon on the insulators below the wire boots.
http://www.flickr.com/photos/23132658@N03/2217514278/

The 1 and 4 wire boots and plugs are clean. The 2 plug seemed really easy to unscrew, while 3 wasn't noticeably easy.

I 'm guessing the plugs weren't tight enough and/or the grommits made a bad seal. Sound right?

Should I worry about using any kind of sealant on the new plugs or just be sure to tighten them properly?

[Venom_5]

could be a number of things ... if its actually oil residue, it could be bad valve seals (nothing to worry about if youre not burning a noticeable amount of oil)

carbon build-up is normal, however .... and i would recommend you Seafoam your engine (do a search in this Gen 3 & 4 section to read about it)

clean it off, put new plugs in ... make sure everything is torqued properly ...

[zanglezonker]

I don't think it's oil. It's more brownish than black, at some places fairly light brown/tan and has no oily feel to it. It feels dry.

I'm now wondering if it might have been due to some arcing between the wire/boot and the tube wall, although I have a hard time imagining the cause of that.

Anyway, I'm putting in new Denso plugs and new NGK wires while I'm at it.

[Venom_5]

it could also just be some rusting if you have had moisture down in those tubes .... idk if you ever wash your engine bay, or have ever got your distributor cap & wires wet