Which is truly the Best Spark Plug For a 2nd Gen 2007 Explorer Sport Trac 4.0 V6?

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Well-Known Member
Feb 27, 2009
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Kailua-Oahu, Hawaii
^ aka Motorcraft SP412

Definitely the OE replacement for your 2008 V6. Appears Motorcraft doesn't have a direct replacement other than nickel. Autolite has Double Platinum APP5143 and Iridium XP5143.

VERY important to check the .054" gap out of the box. Many manufacturers say pre-gapped from the factory, but all it takes is a short drop on the snout, and the center electrode closes.
Also, NGK says anti seize is not needed on their plated plugs. Others say anti seize alters torque and good grounding. Regardless of spark plug plating, I would never consider installing spark plugs in aluminum heads without a light coat of copper or nickel anti seize, especially at these 85K+ intervals. YMMV
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