Fault code P-1314

Model: 996, Year:1999, Mileage:60K, Type of use:Street use only
Just changed Spark plugs, Oil and filter, Fuel filter and added K&N cold air kit. Car was just purchased and has 60k miles, did service to make sure all was fresh and had a starting point for regular maintenance. My car had a rough Idle that seemed to get better when at 180 but not as smooth as should be. After starting the car she had a great idle and ran strong, next day started her and rough idle back and now a stumble off idle still screams once you get going. Check engine light came on so I cleaned the Mas again no change. Did a code read and it came up P1314??? any ideas??Thanks for the help