long reach spark plug

I found this factory label atop the driver's side valve cover indicating a long reach spark plug is to be utilized... Denso plugs are on the right bank and NGK plugs (long reach?) are on the left bank for some peculiar reason... I have a 2013 tacoma with the 4.0 1GR-FE engine. Is there a length difference hence the application of two different brands...

 

For some reason the did that at the factory.

I have the 4.0 as well, and l just use the Denso plugs.

 

Both banks take the exact same spark plugs. There is no difference in requirements from side to side. Toyota has two suppliers for spark plugs NGK and Denso they use them like this to even out their suppliers and that way if one falters they have the other to fall back on.

Just pick one and go with it I prefer Denso.

 

Why doesn't Toyota just put 6 Denso in 1 truck and 6 NGK in the next ?

 

Might be that Toyota had deals with both companies, and to simplify things they just had one brand on one side of the assembly line and the brand on the other side.

That would be easier than changing brands for each vehicle.

 

To confuse the operator, duh.

 

I knew about the NGK/Denso mix from the factory, but I did not know about one set of plugs being "long reach." Interesting.

 

It is not one set of plugs being long reach. All are. It's a style of plug.

 

I'd imagine the plugs get installed in cyl heads in a completely different building then where the engines go in the trucks.

 

I’m waiting for the post that says Toyota owns both Denso/NGK.

And...what other Toyota’s come with plugs from 2 different mfgs?

My opinion on the matter - post #9

https://www.tacomaworld.com/threads/2014-4-0l-spark-plug-question.627604/#post-21466565

 

Because they don't want to.

 

Nope. All the same.
No one seems to know why Toyota used different plugs for each head.
Mine also, had the same 2
All the plugs are the same. I’ve never known anyone to use 2 different plugs when replacing the factory ones.

Hold both the old plugs up, they both have the same reach.

Separate companies, both have some common stock holders.
But they are separate companies.

Here what little research I did on it.

https://www.tacomaworld.com/threads/2015-taco-spark-plug-confusion.674162/page-4#post-23749085


I’m curious if they same thing is going on with the 3.5?