2005 Chevy Cobalt P0171 check out

So this car came in with a running lean condition and some other code I hooked up a scanner and check my fuel trims at an idle which is 800 RPMs my short-term trim was at 2030 and my long-term trim with that 20 steady once I revved up the engine to 2000 RPMs my short-term Trend came down to the lake about 9% and my long-term stayed at 20% I went under the hood and disconnected my mass air flow sensor my short-term and long-term trim swim back to normal short-term negative 4% long term 5% around there I removed the mass air flow and cleaned it with the special cleaner reinstalled it and my check engine light is now off driven it check engine light one car down