Spark plug Denso or AC DELCO

Fresh AC Delco copper core plugs are all you need. Start with the stock replacements and go from there.

I've been running Denso IKH24 for 10k miles, have to swap them often but they've been great so far. Frequent changing will prevent damage to them seeing as they are normal projected grounds, but they are pretty cheap to replace once a year or so.

I run [Denso 5749](https://www.densoproducts.com/denso-5749-ikh01-24-iridium-racing-plug) non projected tip plugs with my FBO IS38 car.

They're 1 step colder, and non projected so the risk of a strap breaking off [\(like this\)](https://i.imgur.com/gdJFaJ4.jpeg) are extremely rare.

I just replaced my spark plugs on my 2012 1.4T with the ACDelco 41-121 ones.

Denso or Bosh are the best you can return and get new ones

Use NGK and if you can’t find them then go Denso. The only 2 plug brands I would put in a Honda.

My 2010 RX350 with the same V6 has 170k on it and still gets me 24 MPG - Denso factory plugs are life, prove me wrong.

The new plug is AC Delco 41-156. Cannot tell any difference in my Gen 2 after replacing plugs. It ran fine before and did afterwards as well.

When I got my S60 (2006, T5) the previous owner had some copper AC Delco plugs made to fit an 850 non turbo in it and I wondered why there was very slow engine response.

Yes! I had a set of iridium spark plugs bought off Amazon that were counterfeit! They were denso but I didn’t discover it till about 40k miles later when I had a misfire. Pulled plugs and they were toast… first set lasted 120k and looked fine..