We have a bone stock 2011 F150 Ecoboost. The truck has a lift and 35" tires but performance wise is stock. We just had the TSB that gave us the new intercooler, cat, and tune and figured with 58k miles of running too rich it might be good to put some fresh plugs in it.


What is the stock spark plug part #? I am finding some sites saying motorcraft sp-528. Does NGK make an equivalent? All my research is giving me results for different plugs for people who are tuning and running more boost (thus changing heat range). I just want a stock style equivalent.

 

The recommended plug is SP-528. This is the current production plug and it supersedes the old SP-512. It's made by NGK for Motorcraft, install them DRY. They come pregapped but you need to check the gap, should be .035.

The only other plug in the Rock Auto catalog for the EB is a Denso Iridium at twice the price.

 

On another forum someone recommended the NGK LFR7AIX iridium. I can get 6 of those for $41 shipped.

The sp528's will be $30 shipped.

 

Most of the performance shops tuning Ecoboosts recommend tightening the gap down to .030 if you're running a tune.

 

Yea I saw that in a lot of threads. A lot of people are saying .32-.34 for stock Eco's.

 

I would put the stock plug back in it. I have a very good friend that is a Ford Master Tech, and he says he sees more random misfire issues on fords because of aftermarket or non OE plugs. NOt sure why, but that is what he said.