What in the world made my spark plugs turn brown?

So I'm driving in my neighborhood and then all of the sudden spudder spudder spudder....like I was running out of gas or not on all 6 cylinders. 1/2 tank of gas - so I go and pull the #1 and the #4 plugs and they are both brown. They were replaced w/in the past 5k miles with new wire/cap/rotor/O2sensors...and last week the I installed the high flow cat.

I drove to Baltimore from central VA last weekend and it did just fine...home from work fine...but this is new to me. And I when I pulled the old plug set before these- they were 100% clean - just the electrode was worn to a pin point.

I'm at a loss here....and I can't find my camera. The plugs are light brown, dry and if I scratch the white electrode with my fingernail it starts to chip off.

Any help???? If I find my camera I'll post up pictures. Plugs are NGKBKR5EYA

 

some additives to fuel cause deposits to accumulate on the plugs.

 

...the only thing I've added to my fuel is more $ out of my wallet....

 

hahaha,lol...

 

lol

the oil / gas companies add stuff to help the gas burn cleaner, reduce emissions, etc.

 

Maybe you've got oil coming thru your intake due to a bad PCV valve, (or some bad oil rings). I had that happen to me on my 22RE. Oil dumping into your combustion chambers will definatley cause sputtering. Although I did have a blown head gasket while this was happening, I was told that that wouldn't cause excess blow-by. Who knows! Go get a PCV valve for $3 and see. It can't hurt.

 

@#$#**&^$@%!!!!!

It the head gasket. That really sucks. Well I guess I'll be sporting my Specalized Allez road bike to work tomorrow....good thing I drive right by the stealership so I can order a good gasket set.