[boxzilla]

I recently came up with a code: 1128/1130 indicating a lean mixture and failing o2 sensor in bank 1/post cat. The addition of fuel addatives may "trick" the o2 sensor ....you might try swapping your bank1 and bank2 o2 sensors to see if the fault follows the sensor. Either way, I just replaced mine at 70k miles as that appears to be the failing point for these sensors. Welcome to CEL Hell!