ok so the plugs on my lsvtec dont have the fuel marks go all aroind the base ring on the plug. well the #3 cyl does its a nice light black. that plug shows no detonation. the other 3 show silver spots. i replaced the intake valve seals as i was getting oil in the cyl that has since stopped. what if the exhaust iz leaking tho and burning in the header. would that be read as fuel by the o2 wideband making my afr appear richer than it is? currently cruising afr is at 14.0:1 and im accelerating at low 13s mid 12s wot. motor is a 12:1 lsvtec with oem itr cams. i know the wideband is good i verified it with anotherr known working one