Denso (3421) SK20HR11 Iridium Long Life Spark Plug, Single Plug

Improves gas mileage with smooth acceleration, easy installation and fits well, very durable original product, excellent price.

One of the cylinders was giving a misfire and I decided to replace the previous autolite spark plug with these higher quality Denso plugs. It worked perfectly out of the box with no need to gap the plug. I would highly recommend these Denso plugs over the other brands.

Identical to the plugs that came in the engine from the factory. Top quality. The plugs still have the original gap after over 100,000 miles. Changed to avoid risk of damage to the aluminum threads in the engine from buildup of combustion by products. Third time to change the plugs at a little over 300,000 miles.

They have passed the extended drive test: Have several thousand miles on these Denso spark plugs now. The 2008 Toyota Tacoma 4-cylinder is running smooth, maintains fuel economy, and has consistent acceleration .

These worked fine even though the Amazon advisor said they are the wrong plug for my truck. It’s the exact same thing. The gaps were not all the same. I had to close the gap down on 3 or 4. The Gap should be .040” nominal. Some of these were around .045” I replaced the plugs at 120,000 miles and the old plugs looked fine. They were still gapped at .043” That was a recommended service interval so I went ahead and did them. The dealer wanted something like 600-700.00 dollars to do it. I saved over 600 dollars doing it myself.

Easy to install. They came pre gapped. 0.044 for tacoma.

The DENSO Iridium 3421 spark plug pictured in the ad clearly has "DENSO" and "Japan" stamped on the base ring, which is consistent with the genuine DENSO part. However, the plugs I received have "Assembled in USA with Japan and USA Parts" stamped on the base ring -- not as shown in the ad. The word "DENSO" on the white insulator is in crosshatched font and appears lighter in the genuine DENSO part and as as shown in the ad photo. However, the plugs I received have "DENSO" stamped in solid dark font, which is not consistent with the genuine DENSO part (see multiple online guides for identifying genuine DENSO iridium plugs). Finally, these plugs are supposed to be pre-gapped at .044". The plugs I received had variable gaps and none met the pre-gap standard. All were gapped at .040 or less. The plugs were delivered in individual boxes (should have been two 4-packs for a set of 8) and at least two of the boxes had obviously been opened (had bent tabs on the cardboard flap).

It is true that the product picture shows "Made in Japan" but the plugs I received were assembled in USA with parts from Japan. Yes, they should update the picture. But I am glad I got these, in the spirit of making local, vocal. Not only does it have precision parts form Japan, it is also precisely assembled in America, a win win. The best part, it fits my 2007 4Runner V6 SR5 4WD. They come with copper plugs so I had a tough time convincing the overlords at the dealership to replace the plugs with these. But they did and my truck runs just fine. It is too early for me to comment on the longevity of these though.

Replace the old ones.

Great OEM replacement. Changed out the Champion plugged installed by previous owner of my 2007 Toyota FJ. Runs great, engine sounds healthier and runs smooth.

Exact replacement for OEM.Definitely long life.

Pas bon pour Volvo 2006 s60 acheter original