Mercury Cougar P Codes (Powertrain) P1100 - P1199

My Daughters Mecury Just Started This Problem A Week Ago, It Sputters In Idel And I Pulled A Obd2 Code P1131 Off Of The Car This Is Telling...

My 1999 Mercury Cougar Has The Ce Light On And The Code Read P1131. I Can't Afford To Take It In To A Shop Right Now, So What Do I Do To Fix...