Answers are correct, low battery voltage can cause drivability problems when voltage drops too low. Probably a bad alternator or wiring issue. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly. This is just a crude check of the charging system.
scanner . try your local auto part store.preferably where you bought the parts.explain to them you replaced the alt. and batt. make sure that charge system isn't for your air conditioner..(quiet possible)