Copper vs. Platinum debate

Yes, copper is generally considered the better conductor for performance but it's life is far shorter.
If you have too much free time, love busting your knuckles, and buying plugs every 10K miles, then go with copper.

After you read this, consider the time, bruised knuckles and challenge involved in changing the plugs on the Ranger V6 passenger side and then you will see the wisdom of going with double platinum for longevity. Iridium is the middle choice. It has better conductivity than platinum but not as good as copper. Yet irridium has better longevity than copper but not as good as platinum, so it presents an in between choice. Irridium plugs are also the most expensive.

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FX4 4X4 SOHC, Automatic, keyless entry, floor mats, radio & heater