What would cause 2009 pontaic g5 to run lean and throw a obd2 code 13 &14

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! Your 2009 Pontiac G5 running lean with OBD2 codes 13 and 14 points to issues in the fuel/air mixture. If the flex pipe is ripped, it can allow extra air into the exhaust system, messing with the oxygen sensor readings, which can definitely cause the car to run lean. Fixing the exhaust leak should help balance that fuel/air mix. Codes 13 and 14 are usually related to O2 sensors, and since you have already replaced them, you’re on the right track. The camshaft actuator solenoid (VVT) might help, too, especially if the timing is slightly off. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554!