[ame]http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf[/ame]I've been reading some articles and it appears that i need a colder plug. Anyone know the next step colder from an FR5?
By the looks of the base where the threads end it is still rich. I've heard this area shows the mixture at cruising speeds. The O2 sensor is in the header collector and there there are zero leaks in the exhaust before it.