Originally Posted by Backinthefold
I just replaced my plugs with some nice Iridiums.
I just did the same with NGK Iridiums, and what a skip in the motor they created
Ides smooth,Rev above 2.700rpms & it misfires like crazy. Almost like you hit the REV Limiter. Bought plugs from RockAuto.com
Going to Ford to buy Motorcrafts, Just learned a big lesson, use oem only in this truck.
BTW: 2007 XLT extacab 4.0 ohc, Auto 4X4.