So at 160,000 miles I replaced my spark plugs with the recommended IZFR6K-13 (NGK) iridium plugs. I had a coil go bad at 172000 and then two more at 188000.

Two of the replaced coils were cheap intermotor coils and I have gone through 4 of them in 12000 miles (2 on each cylinder)

This made me consider that my plugs might have issues. I pulled two plugs and they both looked similar with carbon soot towards the open side of the electrode. The center electrode was significantly worn (2mm gap) considering the old plugs that I pulled out at 162000 still looked basically new.

I was wondering if anyone had any insights on why they would wear out so quickly.

Center electrode worn with 38000 miles

 

So after a little research I discovered that there are counterfeit / fake NGK spark plugs and I think this is what happened to me.

These plugs are toast. The worst one had over a 2mm gap.

I believe that the fake plugs are basically just a copper plug shaped like a fine wire iridium which would explain the super short time to my coils failing. The fine part of the plug probably was destroyed in the first 10,000 miles maybe even sooner.

After comparing my new NGK plugs from Advance Auto (which I hope are real) with the old ones that came out (bought on EBAY) I felt pretty confident that they were fakes because of how different the shape of the ground electrode was. There were other little things but they would be hard to spot without a real plug sitting right next to it.


NGK Fake vs Real

If you look at a similar Ebay listing you will see that the curve on the ground electrode is not very smooth and from what I've seen in the past day of research this may be the easiest way to identify this version of the fake.

NGK Fake - Notice the "kink" in the ground electrode curve. A real NGK will be a very smooth bend.



Here is NGKs official diagram but none of its things to look for applied to mine.

NGK Fakes

So stay vigilante and be careful buying plugs from illegitimate sellers. (This includes Amazon sometimes too!!)

 

Thank you so much for sharing !!
This is why I trying to get my parts either from the store or wrecking yard.
My Denso plugs were $13 each from local O'Reilly's store