Plugs leaking through insulator?

[hmwave]

Just checked some of my IT20's and there are 1/8" long brown 'burn-like' marks showing at the base of the insulator where it enters the metal plug body. There are around eight separate marks around the circumference of the insulator all pointing toward the plug coil end tip, wide at the metal plug body and tapering off to a point as they rise up the plug.

First time I've seen this with maybe three to four sets of Denso's in the last few years. These plugs are around a year old on a daily driver that's seldom driven with full boost.

Are these plugs leaking through the body under compression?
Any cause for concern?

If so I'm thinking about moving to another brand because I'm not sure I want to drop $80'ish on Denso's any longer.

What's the latest recommendation for a 2.8" pullied 2003, brand and gap?

 

[YoungJim]

Take them the **** out!!!!!! My motor ate a chunk of Denso IT20, the bottom 1/2" or so of the center electrode and ceramic. So now I get to pull my motor apart to see how bad it is! If the factory ones are firing the cylinders ok, go with them, anything but those godforsaken densos.

 

[YoungJim]

Sorry, I don't mean to get excited, and I don't mean to say anything bad about you for using the Densos, I just am in the middle of a REALLY bad (read expensive) experience with them.

 

[mavereq]

with your upper you should probably run one heat range colder than stock. i run ngk tr6's. you can go either copper or iridium. the iridiums cost more but last longer. i don't think there is a performance advantage to one over the other. you should run between .032 and .035" gap. i am running a .035" gap but with aftermarket coils.