I've made dozens of road tests with an OTC 4-gas exhaust analyzer running off a 115 volt inverter, and you're right about getting some amazing results. There's nothing that beats actual numbers on the road that not even dyno testing can provide.

The theoretically ideal air/fuel ratio (called "stoichiometric") is 14.7 parts air to 1 part fuel. That's what all closed-loop computer systems are looking for to give the catalytic converter the best shot at controlling exhaust emissions. Best power happens at about 12.5-13:1, and best fuel economy at light throttle comes in at around 15.5:1 or so. It looks like you're pretty close to ideal with the current setup. Adding CO and CO2 readings to the oxygen percentage and air:fuel ratio helps to fine-tune the diagnosis, but that takes a $2500.00 machine the size of a small toolbox!
Jerry

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