[Toystory2]

Hi all,

2007 v6 w/ 169k

Finally got around to changing plugs for the first time since. I purchased the 4R 2 years ago and it had 141k.

I noticed that half the plugs were Denso and the other half NGK. Does that mean these were the original plugs from the factory? I know they shipped some of them with a mix of NGK and Denso.

It would be pretty wild if these had never been changed until now. I hadn’t noticed any performance issues, just wanted to put new plugs in.




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[zguy1]

From my understanding, that is how they came from the factory. Looks to be the original plugs.

[Toystory2]

Originally Posted by zguy1

From my understanding, that is how they came from the factory. Looks to be the original plugs.

That’s my understanding too. Crazy I was able to get almost 170k and not even notice an issue. They looked rough and way out of gap. I can tell it’s running smoother and more powerful, but it ran great before. Also replaced PCV.


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[zguy1]

Yeah it's crazy how well these trucks run on very worn out plugs. When I changed mine for the first time (for me) they were so worn I couldn't believe it.

[Bluesky 07]

Per the maintenance schedule, your truck should have been on its 6th set of plugs (factory, 30K, 60, 90, 120, 150) and 1K away from the 7th. I’ve followed the 30K guideline but this may be the catalyst to extending it to maybe 50-60K. Not using iridium; read somewhere that they aren’t recommended for the 1GR in 4th Gens.

[waypoint]

Can you measure the gaps and report back? It would be good data on long-term wear differences between NGK vs. Denso given your mileage.

I bought my 4Runner at 164K miles and found the factory plugs still there, don't have the notes but I found the Denso plugs had slightly lower gap than the NGKs. All were way over spec, but the Denso plugs were a bit less.

The factory ignition coils seem capable of firing excessively large gaps without overheating and failing, unlike certain other manufacturers. This is a very good thing.

[Toystory2]

Originally Posted by waypoint

Can you measure the gaps and report back? It would be good data on long-term wear differences between NGK vs. Denso given your mileage.

I bought my 4Runner at 164K miles and found the factory plugs still there, don't have the notes but I found the Denso plugs had slightly lower gap than the NGKs. All were way over spec, but the Denso plugs were a bit less.

The factory ignition coils seem capable of firing excessively large gaps without overheating and failing, unlike certain other manufacturers. This is a very good thing.

Oh man, I should have written it down! I know 3 of them were nearly .70, and the other 3 were a little less than that.


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[Toystory2]

Originally Posted by Bluesky 07

Per the maintenance schedule, your truck should have been on its 6th set of plugs (factory, 30K, 60, 90, 120, 150) and 1K away from the 7th. I’ve followed the 30K guideline but this may be the catalyst to extending it to maybe 50-60K. Not using iridium; read somewhere that they aren’t recommended for the 1GR in 4th Gens.

I’ve read that as well. Went with the OEM Denso coppers.


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[Drcoffee]

If 3 were ngk and 3 denso, then yes original from the factory. I switched mine to denso iridium gapped to 0.034”. Runs great and will never wear out. The originals were still in at 220,000 miles and gapped over 0.070” but the engine ran just fine. Its running smoother now of course. And yes you can gap iridiums so long and you dont touch the fine electrode. If you dont gap them, they come gapped too small from denso, your engine wont run right.

Spark Plug Installation | DENSO Auto Parts

I use this tool to gap the plugs. Use the hole in the end to lever open the ground strap.

[AE1M]

Originally Posted by Bluesky 07

Per the maintenance schedule, your truck should have been on its 6th set of plugs (factory, 30K, 60, 90, 120, 150) and 1K away from the 7th. I’ve followed the 30K guideline but this may be the catalyst to extending it to maybe 50-60K. Not using iridium; read somewhere that they aren’t recommended for the 1GR in 4th Gens.

I believe the iridium plugs are 100K mile plugs. I changed mine at 100K, now at 170K on second set. MPG still same as always, about 20 highway.

[MikeinNH67]

So some of these came off the assembly line with half Denso and half NGK? Why would they do that? Seems odd.

When I got my truck the plugs had a ton of mileage on them. Put the correct part number plug in there and it ran way smoother. The old were toast, probably due to be changed again on the normal interval.

[eleven14]

The only thing that makes sense to me regarding the two different brands from the factory was Toyota wanting to maintain supply balance between both suppliers so they went 50/50. It's the same with Tacomas.

And I'm on original plugs at 155k miles. I keep intending to swap them but the truck runs fine so I keep kicking that can. Just finished a ski trip, 10 hours each way, with zero issues.

I'm sure those plugs look gnarly, I'll grab pics and gap them whenever I get to it for fun.

[Bluesky 07]

Originally Posted by Drcoffee

If 3 were ngk and 3 denso, then yes original from the factory. I switched mine to denso iridium gapped to 0.034”. Runs great and will never wear out. The originals were still in at 220,000 miles and gapped over 0.070” but the engine ran just fine. Its running smoother now of course. And yes you can gap iridiums so long and you dont touch the fine electrode. If you dont gap them, they come gapped too small from denso, your engine wont run right.

Spark Plug Installation | DENSO Auto Parts

I use this tool to gap the plugs. Use the hole in the end to lever open the ground strap.

Curious, why are those gapped differently?

[twa318]

Yes originals, one side of the assembly line had denso and the other side NGK.

I still was running the originals @ 240k miles when I replaced them, truck ran fine.

https://www.toyota-4runner.org/3765085-post2.html

[Lemon_runner]

Wow! Just changed mine at 161k and the gap was around .085 for both sides. Seemed the denso plugs came out easier. Wish that I took pics now.