New to forum I just bought a b16a2 and noticed that cylinder 4 and 3 exhaust valves are white and 1 and 2 are not. I was thinking it's from heat or running to lean but why only on 2 cylinders? The guy I got my motor off was running a p72 ecu which I kno is not meant for it because of the butterfly valve on the gsr was thinking that May have something to do with it any helps appreciated thanks