I just did the plugs on our 150k CRV. It has run on 500:1 2C since I pulled and clean the plugs 30k ago. Plain NGK v-Power installed at 90k. They wore out to .055 from .044 after re-gap. Time to replace. Used NGK again, Iridium-IV and it runs nice and smooth. So, the plugs look clean and worn, just a hit of grey ash. Highway trips and the 2C oil, like I mentioned. Some people think the 2C will foul plugs or whatever. I still use it.