Question about spark plugs....What side had the NGK/Denso from factory?

[denvertoyota]

So I decided to replace my plugs. 5 of them where denso, and looked newer. ONE however, was in real bad shape and was a NGK. The NGK was on the middle cylinder on the passenger side. Is that possibly an OEM plug? Is the passenger side head the one that came with NGK? I replaced them with the dual tip recommended part number DENSO plugs from rockauto. I got all plugs, and PCV valve including shipping for $21.00. The whole removal install only took about 30 mins. Its real simple. ( I love toyotas!)

The plug replacements seemed to have given me a smoother idle, as I could sense a slight miss. I assume it was that sub-par NGK. My plug wires are OEM and sumitomo stamped. They are in good shape.

Also, on an emissions test, if your combustion temperatures are somewhat high, could it be a bad plug as described? I really didnt have a bad E-test, but it was at 75% of the limits on the combustion temp test. It did pass, im just on a quest to have the best running engine possible. next up, "lifetime" fuel filter change.:banana:

Thanks Everyone!

 

[cfranck1]

So I decided to replace my plugs. 5 of them where denso, and looked newer. ONE however, was in real bad shape and was a NGK. The NGK was on the middle cylinder on the passenger side. Is that possibly an OEM plug? Is the passenger side head the one that came with NGK?

Thanks Everyone!

NGKs on the passenger side and Densos on the Drivers side.
I think they only came that way from the factory.

 

[Jon]

I'm new to Toyota, but running different plugs sounds like a really bad idea. Just today I replaced all 6 Denso plugs with NGX Iridiums. Runs much better. I have a simple philosophy: NGK for imports, Autolite in the Domestic V8's. I understand that the 3.4 may be an exception due to coil-on-plug on pass side and wires to the driver's side. It's all up to the engineer specs. I'm pretty sure they knew what they were doing. But for the record, the Densos that I pulled out all looked the same as far as carbon build up and burn which was really bad. My 66 Galaxie's plugs have never looked that bad. Maybe I keep the carbon from building up by always keeping my foot in the floor, I'm pretty sure the previous owner of my 4Runner was nursing the gas pedal, (330k mi and no smoke).

Just to back this up, I work the flight line at an Air Force base and the speed limit is 15mph. The trucks we use are driven 24/7 and they are crapping out all the time. Long story short, engines need to be run out to max rpm every once and a while to burn off naturally occurring carbon buildup/keep it from building period.

 

[zcruiser]

Jon - Came that way from the factory. Something having to do with an even consumption of both NGK and Denso plugs across production volumes or something odd like that...

I don't think anyone actually replaces with NGK on pass side and Denso on driver's side just to make it like factory.

Kind of an inside joke...

 

[notrayray]

Jon - Came that way from the factory. Something having to do with an even consumption of both NGK and Denso plugs across production volumes or something odd like that...

From what I heard the heads where assembled at two different locations....don't know if it's true, just what I heard. :cheers:

 

[XJeepguy]

Quick question . Do your Sumitomo plug wires have the year stamped on them ?

Thanks !!

So I decided to replace my plugs. 5 of them where denso, and looked newer. ONE however, was in real bad shape and was a NGK. The NGK was on the middle cylinder on the passenger side. Is that possibly an OEM plug? Is the passenger side head the one that came with NGK? I replaced them with the dual tip recommended part number DENSO plugs from rockauto. I got all plugs, and PCV valve including shipping for $21.00. The whole removal install only took about 30 mins. Its real simple. ( I love toyotas!)

The plug replacements seemed to have given me a smoother idle, as I could sense a slight miss. I assume it was that sub-par NGK. My plug wires are OEM and sumitomo stamped. They are in good shape.

Also, on an emissions test, if your combustion temperatures are somewhat high, could it be a bad plug as described? I really didnt have a bad E-test, but it was at 75% of the limits on the combustion temp test. It did pass, im just on a quest to have the best running engine possible. next up, "lifetime" fuel filter change.:banana:

Thanks Everyone!

 

[notrayray]

Quick question . Do your Sumitomo plug wires have the year stamped on them ?

Thanks !!

Mine do...... :

 

[zcruiser]

From what I heard the heads where assembled at two different locations....don't know if it's true, just what I heard. :cheers:

Yeah, that was part of the story too. One location used Denso and the other NGK, again to assure an even consumption from each vendor. Pretty odd, but that's sometimes how contracts get written up.

 

[denvertoyota]

Quick question . Do your Sumitomo plug wires have the year stamped on them ?

Thanks !!

Huh I guess they do. mine say 2001. This thing idles as if its not even on, so I am not going to bother replacing the 9 year old wires.

 

[XJeepguy]

I wasn't totally sure if that was a year code or not . Mine say 2006 so guess they should be ok for a while . Thanks man !

Huh I guess they do. mine say 2001. This thing idles as if its not even on, so I am not going to bother replacing the 9 year old wires.