Hello all,

I've done some searching, and can't seem to find a straight answer on this one, as it appears to vary with the model year. I have a 2014 5.0L. What is the correct spark plug gap for this truck? What are the impacts if the gap is too narrow or too wide? I changed my plugs from the OEM a few thousand miles ago, and it seems that my truck is more sluggish now, and mpg has dropped a little.

Thanks

 

What did you change them to? The OEM plugs are pretty much the best for these trucks, no reason to leave. Gap should be about .050, perhaps just smaller. That info is in the manual, and I haven't seen anything worthwhile to contradict it. When the gap gets larger, as it will with time, idling will get rougher and performance may drop a bit. The recommended life is 100k miles, but they seem to need a gap adjustment (or replacement) by 50k.

 

.049-.053 in. *as per your owner's manual.

(owner's manual) Don't have one -OR- would like a digital, searchable desktop document?.

 

If the service life is 100,000miles they must be iridium. I suggest taking them out about 30,000miles and just putting antisieze on the threads and putting them back. if you wait till 100,000 the plugs may come out with the head threads.

 

A standard double platinum plug (platinum ground, platinum electrode) will easily carry the load for that long, which by the way is what the OEM plugs are and have been since the late 90's. Imagine that!
.

 

The factory SP519/CYFS-12Y for the Coyote were not double platinum, they had "iridium" printed right on them. They went back to double platinum when they replaced those with SP548/CYFS-12F1.

 

I have always just soaked them in penetrating oil for 24 hrs, warm engine, wait till cool, never had a problem at 100k miles.
But that is just personal vehicles, I don’t get paid to fix them.

 

I've seen a lot of fords with the 10mm plugs that had to have the threads repaired. It was llike a dotage industry for awhile. your choice.

 

With my luck, the threads would come out while trying preventative maintenance to keep the threads from coming out.
I only have 50k miles now, and it may be 10 yrs before I hit 100k, I’ll wait.

 

it costs you nothing but some time to r&r the plugs and put anti-seize on. repairing heads will cost a lot. your choice.