Spark plug Bosch or Denso

New Denso Platinum spark plugs. Car drives great, no codes, no sputtering or stalling or hesitation.

Fitting a decent set (Denso or NGK) of iridium plugs is also worthwhile.

August 28 2024 : Spark plug change Bosch 70,588

I run more or less the same motor (2.1liter-276 Schrick-10.5CR), and I'm using stock Bosch spark plugs.

Denso 3457 (FXE24HR11)

Why? It's the plug recommended in the owner's manual and I have never seen anyone have issues with this plug.

Why are they noticeably better than other equivalent plugs from reputable brands, I honestly don't know as it seems that the differences should be negligible. Plugs are one of the areas where the car is very fussy.

Swapped the NGKs (around 60k miles on them) for new OEM Denso plugs. That stopped the shaking for about two days, then it came back.

I don't use spark plugs like that unless the vehicle specifically specs for them. We used to put Bosch W7DTC's in these, or at a minimum, just the single electrode version.

I wish my Toyota 4Runner spark plug service was that cheap in the Toyota dealer. I was quoted $800 parts + labor for OEM Denso.

I highly recommend avoiding anything other than exactly what is specified in your owners manual, I currently have bad gas mileage because I was too curious to see if the desno two tip would do as good as the other stuff.

If it is the skyactive-x be aware that the owners manual advises spark plug replacement at 40k miles and the Mazda plugs are \u00a340 each. I put aftermarket Bosch plugs in and it ran very lumpy and had to replace with Mazda ones.