Replaced Spark Plugs - NGK G-Power
 

The G-Power seemed to be one of the recommendations for the V6. I did a search on
G-Power plugs, and got some videos recommending them for the Mustang 4.0, so I
picked up a set.
https://cimg8.ibsrv.net/gimg/mustang...73729f062f.jpg


Mine came out relatively easy, nothing broke, and they were pretty bad:
https://cimg1.ibsrv.net/gimg/mustang...9969b60dca.jpg

https://cimg4.ibsrv.net/gimg/mustang...aad07e4e0b.jpg

Every plug looked about the same or worse, and they all smelled like fuel.

Started up much quicker, and smoothed out the idle. I have been getting about 25MPG, so will run this
Sunday and see what it gets.

How many miles did the motorcraft plugs have on them?

I remember when I used to get 25+ MPG from my 4.0

Not sure, I took them out with the odometer at 103,000 or so. I would imagine that
they were changed at one point, thought the CarFax shows they were never done, so
if they were, it was not at a dealer.

My best was damn near 28MPG with the 93 octane fuel and tune. I actually get less MPG
with the 87 performance, or economy tune. So, I have kept it at the 93 Performance tune.