Spark plugs suggestion

[ddongbap]

Also, why replace them after 100k mles? Is that some sort of magical number that sudenly makes a plug go bad or, do they deteriorate gradually over their life ?

So what you're saying is the smart people with tons of money who work at these companies are just saying 100k miles cause they decided to pull that one out of the air?

I challange anyone to show me a dyno report that shows that performance is exactly the same with new plugs and with plugs with over about 75k miles on them.

I challenge you to show me a Yaris dyno report that shows SIGNIFICANT power loss due to older plugs.