Micah-
What part number are you using for NGK Double Platinums?

NGK does not list any double platinum (or irridium) plugs for the Duratec.

This is the main reason I would not recommend NGK's to anyone with the Duratec. (Nitrous users excluded)

As for their quality otherwise. Top notch.

My recommendation is Autolite APP764 or Motorcraft AWSF32PP.

For those Forced Induction, 3L Hybrid & chipped folks I recommend AWSF22FS plugs. There may be an Autolite equivalent???

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.