Fitech running fat

I don't think it's an IAC issue. If the system was unable to achieve Target AFR, then I'd look there. Basically the system is happily doing what it is supposed to, adjust fueling to reach it's Target AFR. The problem is, it's not accurately sensing the AFR. Fresh air is being introduced on the monitored bank altering the AFR, the sensor is faulty, or that monitored bank is actually at correct AFR but the other bank has a dead/failing cylinder or other issue pumping fuel into the exhaust. My money says it's an exhaust leak.