Originally Posted by Epstein

You may be self-learning yourself into a hole. The A/F Alpha learned value only comes into play at low throttle. Once you exceed that throttle position, you go back to the map value. If you've learned way too lean, the car will be slow and jerky, especially since the ECU will probably pull timing since not-cool things are probably happening at mega lean cruise. Self-learn is completely dictated by O2 sensor.