New denso iridium POWER plugs 2007 yaris

["G"]

Just installed the 2nd set. Love these things. First set installed around 180k in Jan of 2015. I now have 280k and the CEL came on. The code was for a misfire on cyl 1. I knew it was the plugs because it's the same code I had last time I replaced them in 2015. Anyway here are some pics, highly recommend these. Not only because of the increased power but increased gas mileage over the stock oem plug. I did notice the yaris was a little sluggish the last week or so. Looking at the plugs I now see why.

https://www.amazon.com/gp/product/B0032YE1JM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

https://i.postimg.cc/ncTyNP5j/IMG-3379.jpg (https://postimg.cc/qzhD3jp4)

https://i.postimg.cc/P5RB58dd/IMG-3380.jpg (https://postimg.cc/5X8PPyHr)

https://i.postimg.cc/BvPRLQvH/IMG-3381.jpg (https://postimg.cc/R39g2mKZ)

https://i.postimg.cc/pTN4Db97/IMG-3382.jpg (https://postimg.cc/PL4Sj7Qz)

upload a photo (https://postimages.org/)

[dogsridewith]

I don't see how you could possibly love those power iridiums. OEM plugs are supposed to go 120 kmiles...and certainly never look like that. I did plugs at 135 kmiles and plugs had no wear or extra gap. (Don't know if they had ever been changed, but everything to get to them came apart with a sort of new-part factory crisp break. SoCal chick-owned car w/ likely original battery and serpentine belt @ 134k/10 years)

[dogsridewith]

I know of no reason but loose installation, or got loose, for all the carbon on the lower ends of the outside of the plugs. Which meant heat transfer was lost. Which would have made the whole plug run hotter. And burned up the ground electrodes?

["G"]

I checked the mileage again and it was closer to 100k when I installed these. So 180k miles on this set. Not bad. I'm in the great lakes region where we have shitty winter blend gas and I also used some seafoam in the tank a month ago so that's more than likely why the deposits. They were installed nice and tight.

The black goo on the threaded body area is just anti-seize.

[alanwagen]

My 2 cents. NGK plugs have treated threads and advise DO NOT use anti seize as it will change the torque values and you could end up striping you threads. I have had very good luck with the NGK plugs.

http://ricksfreeautorepairadvice.com/anti-seize-spark-plug-threads/

["G"]

Denso are treated as well. Yes anti-seize is not recommended for denso either. But i only used a small amount since i knew they would be in the head for over 100k. Torque values? Yes that is true been when's the last time you used a torque wrench on plugs? Exactly never.

[alanwagen]

Denso are treated as well. Yes anti-seize is not recommended for denso either. But i only used a small amount since i knew they would be in the head for over 100k. Torque values? Yes that is true been when's the last time you used a torque wrench on plugs? Exactly never.

Torque values are also by feel. You could over torque it because of the lubrication action.
Also, using too much anti-seize could compromise the negative grounding, diminishing spark. I believe the engineers that make these plugs know more than you and me so I yield to their advise.

["G"]

I follow the tightening directions and haven't had a problem yet.

[tmontague]

I believe the engineers that make these plugs know more than you and me so I yield to their advise.

Sure, except they are not the ones having to deal with seized plugs down the road. I always use a small amount of anti seize ad hand snug them. Never an issue on either my heavily tracked yaris or my families Vibe.

To each their own, however the recommendation that the engineers or the manufacturer knows better is an old one that doesnt hold much weight for many things involving cars. Oftentimes a decision like that will be made simply because if one or two DIY'ers who will over apply and foul a plug. This fear causes a blanket statement to be made and is not necessarily in the best interest of a knowledgable DIY'er.
- just ask all of those Ford truck owners how happy they are that the factory didn't apply anti seize to their plugs, since they know the best and all...