My pump seems to have not good suction, should I buy new pump ? Or change the parts? Using spectra 9+

Is your pump still under warranty? If it is not, you can also consider sending it for servicing: http://www.spectrababy.sg/pages/terms According to their terms, for expired warranty set, the servicing fee will be $30. Additional charges are also applicable for the parts replaced. Pump parts are priced between $14 to $69.