Plug fouling question

[fastivaca]

Hello all,

I just pulled the plugs from my B6 and found that #3 & #4 were fouled in a way I don't think I've seen before. It looks like they're only fouled on one side. I've got a couple of photos that I hope show what I mean...





Any ideas what might cause this? They are NGK BPR5EY11

Thanks

[IL4Festiva]

looks almost like corrosion on the metal.. u got no fuel/oil additives in your car? i ain't a mechanic but.. to give something like that u gotta be burning something other than gasoline i would imagine..
it does not make sense for just one side to have it though.. unless something is burning in the cylinder that burns slower/faster than gasoline, and shifts to one side or another.. but none of that should be happening as far as i know. your # 1 and 2 are not fouled at all?
Maybe crappy sparkplugs? :S

[jglutz]

That plug does not look all that bad....I've seen alot worst.
A couple of things to consider:
1) When evaluating plugs, it is better to pull them form a hot engine...all of the cold start problems will be burned off.
2) Wear the plugs loose...that discoleration looks allitle like blow-by.
3) When was the last time you change the plugs, wires, rotor or cap. The pict could be poor spark.

[FestYboy]

poor burning of the additives that are in the fuel you're using causes that kind of build up.

[fastivaca]

Changed plugs, wires, cap and rotor and the problems that prompted to pull the plugs in the first place have been corrected. The plugs themselves were really loose so that was probably a contributing factor too.

Thanks for the input.