Plug Readers Chime In

I've seen blue, green, and rose colors on plugs in the past..... always figured it was from additives.

IMHO, the above 'lean and hot' reads are getting fooled by the modern fuels. Put an AFR gauge on it, and it will be in the 14-15 range cruising (maybe a tad higher even), which is fine, and really where it is supposed to be for regular driving.