IrinaT

I have an engine light for a almost a year now. First error was P0171 - replaced oxygen censor and vacuum hose. After driving around the corner the same error came up, and now half year later I decided to check again what is engine light means. Today pulled out three codes P1150, P0440, P0171. I reset battery and engine light went off, went to do emission test - passed. Drove few miles and light came up again. Any advise? What else to replace?