In the middle of my cam swap, I was debating putting some new iridium spark plugs in my truck. I doubt I really need them, but since i had my motor broke down I thought I might as well considering that I thought a set of iridiums might give a little better power because of their easier spark. I assumed we had platinum plugs from the factory. Well I just took one of mine out--- and I think I have iridium plugs. It is a NGK DILFR5A-11, and the main factor is it says IR in big blue letters on the side. From what I can find platinums have R on the side and laser iridiums have IR on the side. So is this a iridium plug????
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