Are they Motorcraft? If not, I'd recommend changing them.

Also, about 10 years 100k they should be changed anyways.

 

Back a decade ago, I picked up some discount spark plugs & wires......never used them. They sat behind the seat of the truck for at least 10 years. Amazon.com sold the plugs for $0.88. 88 cents a plug. The wires were Autolite. From my fuzzy memory, it was all about $20 or so. I remember my buddy laughing and saying that I should just spend whatever to buy Motorcraft. I just installed them this week. For anyone who is interested, they work fine. No problem what-so-ever. Admittedly, much of what you see in regards to E3 sounds like hokum and it's all just a bunch of advertising lies. No way that a spark plug can do everything that they claim, right? But they do work. Engine runs.

Part #s:

E3 Spark Plug E3.60

Autolite 97045