Spark plug insulator cracks

[Kensi]

2004 GTP compG 80K miles.

#3 spark plug has recurring issue with the insulator cracking. Replaced it twice now after about 1500 miles. Replaced all the plugs and no issue with them. What say ye experts?

[FordMan77]

What brand/type of plugs are you installing? Are you using an actual spark plug socket or just a normal one? Anything in the area that may be hitting the plug?

[BillBoost37]

Insulator on the exterior? That's plug socket and or angle when tightening.

[Kensi]

Insulator is not cracking on installation. Plugs are OEM. As I said, it takes awhile before the engine begins to miss. This plug is front and center on the engine, no issues with angle or access.

[Kensi]

Insulator is not cracking on installation. Plugs are OEM. As I said, it takes awhile before the engine begins to miss. This plug is front and center as you look at the engine from the front of the car, no issues with angle or access. Crack appears and runs from the terminal down through the ribs of the ceramic insulator.

[BillBoost37]

And it's definately cracking and not say carbon tracking etc?

[Wotgtp]

I'm going to suggest it's install error. Unless that part of the head is flexing so badly that it cracks the ceramic, but I'm sure you'd have far bigger problems then cracking plugs.

[Wotgtp]

Or you could just be buying a bad batch of plugs. When you need to change out the #3 plug, swap it out with another (like #1 or #5) and put the purchased replacement in that cylinders place. See what happens.

[Kensi]

The carbon tracking idea seems to ring the closest. Would this issue cause misfire?

[BillBoost37]

It can. Usually it would be from a plug or wire. Sometimes a coil that isn't firing up to it's potential.