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      10-09-2012, 08:44 PM   #9
micah_675
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Drives: 2006 325i (US Spec)
Join Date: Sep 2010
Location: Germany

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Black is oil burning/residue on your spark plugs. The brown/whitish is normal. See this as a guide for what your plugs are telling you about your motor.....

http://www.mudinmyblood.net/forum/im...park_plugs.jpg

More than likely the plug that is fouled black, is from oil dripping onto the top of the plug and slowly seeping through. This will cause oil fouling on your plug and on the contact. It was probably the plug right next to your 710 cap.