I get the best plug colors with 14.5 AFR or leaner(up to 15.5 AFR cruise or idle) at idle and light part throttle cruise RPM below 2500 RPM up scope
I agree with the mad scientest on plug colors, white to very light tan is perfect up
Dominic and I have seen the same thing your seeing and feeling with the AFR rich, richer feels good but leaner is meaner except at WOT up

Last edited by Cab_Burge; 07/30/18 02:53 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)