when car is cold she starts fine but after it warms up she wont start on 1999 Buick Regal

it will turn over but sounds like starving for fuel,could not hear pump run until after it cools off.changed pump(got it from scrap yard)everything seemed to work fine .after a couple of weeks it started to act the same but this time i could hear the pump run even when warmed upbut makes wierd noise

Asked by for the 1999 Buick Regal