For carbureted engines, ensure sufficient fuel, inspect fuel lines for leaks or damage, and test for a strong gasoline spurt when cranking the engine. If weak, assess the fuel pump and its flow capacity; it should pump a pint in 30 seconds. For fuel-injected engines, listen for the pump's whirring noise on ignition. If silent, inspect the fuse, relay, and circuit. To test the pump, apply battery voltage to its gray wire terminal. To verify the relay, use a test light and jumper wire. If there's an issue with fuel pressure, connect a gauge and check when the ignition is on. Low pressure might indicate a defective regulator, and high pressure could signify a blockage or faulty regulator. On MPFI models, check the regulator's function by observing pressure changes when detaching its vacuum hose.