GordnadoCRD wrote:
I've heard this before from a handful of experienced mechanics I trust. It seems to have something to do with systems using individual coils per cylinder, but I don't know what the mechanism is causing the damage. Could you expound on that?
The ignition system is designed with a built in resistance factor for proper function.Changing that resistance via spark plugs will burn out the coils.Plus one has to consider heat ranges,the OE spec plug has the correct heat range but that fancy $15 iridium plug that autozone tries to force you to buy will not have the correct heat range,may fit and work but not correctly.
Besides heat range you would need to re-gap the platinum/iridium plugs to get close to the correct copper/nickle plugs that are the correct plugs for the 3.7.
OE copper/nickle - 0.040"
Platinum would need a gap increase to about 0.065"
Iridium would need a gap increase to about 0.085"
But doing that with the incorrect heat range will cause misfire and possible piston damage.