Took my plugs out this weekend, and noticed that one plug was discolored, slightly brownish... The rest of the plugs were completely white, this one came out slightly brown. What's the deal?

 

I suppose if its a light tan it could be ash deposits like a slight oil burn situation.

 

Yellowing of all of the plugs normally indicates that a fuel additive was in the car. Torco used to do this when it was used way back when....but this was just one, so...

My best guess (if all is well, how'sshe running?) would be that the plug was from a different batch than the others, maybe a different plant. Make sure that when you change plugs next time to remember to see if the same color variation is there. If there is, it would not be a bad idea to do a check on leakdown/compression, injector (debris in pintle filter) and coil pack/wire for that particular cylinder.

 

Actually ran some Gumout for the e85 not too long ago, that might be it... Thanks Tallen