I have a 99 Chevy Monte Carlo and I just replaced the fuel pump the other day. Since I got the car restarted it runs good but when I mash the gas down to really get up speed it hesitates & sputters.
Did you replace the fuel filter also? If you did then you may have a fuel pressure regulator going bad or the fuel pump is not making enough pressure even though it is new. Test the fuel pressure and flow rate. You may want to reset the ECM after everything is done.
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