Spark plug NGK or Autolite

I run these on my stage 2 2019. Runs great. Like zero knock. Sometimes idle seems a bit less smooth when engine really hot but tach holds dead steady. Ran a set for 5k, inspected and put back in for another 5k then replaced with a fresh set and have another 2k on the new set.

I use NGK... it's the same 1/16 turn instructions on my Suzuki outboard (also NGK) and I use the same method of 1/4 -1/2 turn. Been good with those over 6 or 7 changes.

I was told that the Motorcraft iridium's are made by NGK?

You're on the right track- replace those worn out plugs. Pre-detonation started on my '18 at 30k. Increasing octane rating to 93 worked up to 58k miles. $50 for a new set of [Autolite Iridium XP5363](https://www.amazon.com/dp/B078KWTCF2?ref=ppx_pop_mob_ap_share) resolved this problem.

I opted for the NGK DIFR6D13, since these were suggested by a local Honda dealership. These seem to be perfectly fine for the CR-Z. No complaints at all.

I've been running the NGK "rs7" plugs 06K905601M in my wagon since I went IS20 with an APR stage 3 91 tune. Stock gap out of the box was .026. I've now put about 6k on them and have had zero issues.

I have NGK ruthenium’s and it is noticeably smoother at idle vs iridium’s. Literally zero idle “pop” or misfires

That’s curious….. if you look closely at the end of the shorter plug you can see another set of threads, it looks like there an insert threaded onto that spark plug. It would appear that it wouldn’t be sitting where it needs to in the combustion chamber so that may explain your misfire.

Auto lights are trash, Bosch too. I can’t tell you how many times I get a misfire diag that the customer already put plugs in, only to find the garbage auto lights are the issue. A set of oem plugs always fixes it

On my stage 2 mk7 I swapped around and tried a few like ngk and the ngk failed causing misfires like crazy on acceleration. Back to OEM and never had another issue for 45k miles.