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

Maybe the flanges or nipples are not the right size? Usually if it's a suction problem usually could be those two thing. Also, you might want to check the suction, even the tiniest of hairline cracks can mess with the pressure and suction of your breast pump. If so, you can just replace the damaged parts.