Spark plug Bosch or Denso

I've never had any issues with Denso plugs, so I recommend those :)

The new ignition switch is in. The spark plug wires are Bosch copper and now have the Bosch super 3 ground electrode plugs installed. So with a fresh ignition switch that eliminated the odd electrical changes we were seeing in the dash lights, now stronger cranking and it does run better.

Bosch W6DPO. They’ve always been expensive, but now stupidly so. I’m not paying $250 for plugs, either. The DENSO IW20TT you referenced is a perfect replacement because it’s the exact same heat range as the W6DPO.

Yes definitely get the original OEM Denso plugs and be really cautious of anything you purchase off Amazon a lot of them are counterfeits. You can either go direct to the Toyota dealer or you can go to your local parts store like Napa and just make sure you order the correct Denso Plug.

The plugs look really good pretty even color across all of them no major carbon buildup. Wear on the plug seems typical for 100,000 miles.

That said, make sure they use quality parts. BMW/Bosch spark plugs and OEM pulleys (and belt) are a must. NGK plugs are cheaper and don\u2019t last as long. Same goes for off-brand belts and pulleys.

Took original plugs out at 50K miles. Not awful but electrode partially rounded with increased gaps. Stock plugs are Bosch and apparently copper core, so I replaced with same. Recommended gap is 0.043'' Added anti-sieze to threads for easier removal next time.

They're both fine brands, I doubt you'll notice a difference. NGK is most likely OEM for your Civic, but it's not like Bosch is bad, they're OEM in my BMW.

Im running denso step 2 cold plugs from bms website and tbh i regret not going with the hks plugs

Champion is OEM and what we suggest at work, but NGK has never failed us with any application. Bosch is generally terrible and we only use them if it’s a very specific application.

I got some phony Denso marked spark plugs