DorianL said:Regardless of what the A/F would say on the wide band... with each run the tail pipes would STINK rich...
some times indicating a retarding ignition timing allowing some of the yet unburnt fuel to be scavenged out the exhaust,past /trapped in the header primairy when the exhaust valve closes to remain un burnt until ignited by the next exhaust pulse where it won,t burn completely due to lack of oxygen or an exhaust header design, matched to cam timing that's scavenging some of the new charge thru the cylinder and sucking into the exhaust before the valves close as the high pressure intake charge fills the cylinders (nothing wrong as it tends to clear the old exhaust effectively but the MILEAGE might suffer)