In the land before time and EFI...people actually removed their sparkplugs and studied them....some with a magnifying glass even!xRoller said:if your car is leaning out? i have a 98rs with a jcsports intake seems to be running fine? And will it extended use eventually do something to the motor?
I think you're safe. We have our SAFC dialed to lean the mix between 5-12% across the board with the exception of just off idle tip in, where we have a few % enrichment. There's still room to go leaner too but we aren't up to risking anything just yet. This is a 98RS w/ WeaponR intake, K&N filter, Borla header, and SPT exhaust. Monitoring is done with A/F gauge and SAFC.
You can read your own plugs, there's info on how to in every Chiltons or Haynes manual.