A/F/R gauge for tuning

I don't think you could see that on an average of 4 cylinders? I jetted mine to read an average of 15 - 15.5 A/F while cruising an my car ran great..no bog or hesitation at all. It is a stock build with a small cam. Because the reading is an average of 4 cylinders my thought was that i could have a lean cylinder and wouldn't know it so i jetted back to a cruise A/F of 14 - 14.5. My gauge changes numerous times per second and i don't see anything that isn't occuring full time on average.