Negative Positive
Title: Doesn't perform for the whole 100k miles.
Review: I installed these on my 5.4 Ford Expedition at 90,000 miles back in 2006. It is now 150,000 thousand mile and I am having some drive-ability issues which is a light misfire not picked up by the computer. I traced it back to the plugs. I installed new ones and the issue is fixed. I guess this is why they only warranty for three years because they do not have the actual 100k performance they mention.
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