What's this stuff on my plugs?

[Barry Bordes]

Originally Posted by turbovert91

OK, my car started running jerky/hesitating on accel after 1/4 tank of fuel just after being tuned. I pulled the spark plugs and this is what they look like:



Does anyone know what the residue on there is? I'm running the NGK race plugs (R6725-105) and 110 octane leaded race gas. fuel...any input/thoughts are appreciated, thanks.

Not to be a wise guy but it looks like fuel additives collecting on hot plugs, i.e. lead. This is what it looks like on aircraft plugs.
Barry