Anyone use Iridium plugs?
Thinking of upgrading the double platinum stockers. Closing in on 80k since the record says they were done last.

Thinking of Denso TT's, Maybe NGK or Autolite. Motorcraft does not have one. Lots of choice for this engine.

 

IMHO, keep the oem plugs.... just not going to get any better.

 

Some say they increase mileage, but may be better not to poke the sleeping bear.

 

i use NGK Iridium IX plugs but im not stock and will have more changes coming next month. if your stock or just tuned go oem, they are cheaper and you got 16 to replace.

 

For a Ford engine, I will never use anything but Motorcraft plugs. I've heard more bad than good about any other aftermarket plug.

 

you could also use autolite plugs cause that who makes them for motorcraft

 

They also make an iridium for this application. Seem lots of other cars use this size, including GM midsize SUVs, Ford N/A 3.5L

The 3.5 ecoboosts have a similar plug and its specified Iridium.