WHAT DOES 4AGE 20V ITB MEAN?

Why would the carbs being unsynched transform theAFR? Some cyls would operate abundant an some lean but When the O2 is Doing the job then it can nevertheless regular out to stoich.the next take off is on major from the ITB and this is connects to at the rear of the throttle plate and give great vacuum (suit the map sensor there)Approximated supply