O/2 Sensor location

[Ed Wright]

Art, is the coolant temp the same? Anytime I have had one pop & bang it has looked lean. If the engine is cooler I would guess it's a tad lean. My stuff always goes down the track quickest richer than the dyno liked. If your problem is at lower temps you might try adding a little fuel in your air/fuel coolant temp correction table, at the temp you are seeing first pass. That's providing you don't warm
It up to the same temp it runs at the rest of the day.