Will start up runs for a few seconds and then dies

Check fuel pressure should be 30 psi at idle you will need an adapter to do this here is how to test fp
Constant fuel pressure is maintained in fuel lines and component parts at all times. Relieve pressure before attempting to open system for testing. Do not allow fuel to flow onto engine or electrical parts or allow an open flame in area while testing fuel system components.

To release fuel system pressure on 280ZX and 280ZX Turbo models, start engine and unplug fuel pump electrical connector in luggage compartment. After engine stalls, crank engine 2 or 3 times, turn ignition "OFF". Connect fuel pump electrical connector.
On Maxima and 200SX models, start engine, disconnect fuel pump relay. Fuel pump relay is located on the right front fender. After engine stalls, crank engine 2 or 3 times, turn ignition "OFF". Connect No. 2 fuel pump relay.
Remove fuel filter-to-fuel rail hose and connect a pressure gauge using a "T" fitting. Start engine and read fuel pressure at idle. If pressure is not as specified, replace pressure regulator and repeat test.
Disconnect vacuum line from fuel pressure regulator and connect a vacuum pump. On 280ZX and 280ZX Turbo models, disconnect fuel pump connector. Apply battery power. On Maxima and 200SX models, remove fuel pump relay and place jumper wire between Light Green/Red and Black/White wire in harness connector. Turn ignition "ON".
On all models, as vacuum is applied to pressure regulator, pressure reading should decrease. See Datsun/Nissan Fuel Pressure Specifications table. If pressure and vacuum readings do not conform to specifications, replace fuel pressure regulator.
FUEL PRESSURE SPECIFICATIONS
Condition: In. HgPressure: psi (kg/cm2 )
Idle (1) 30 (2.1)
036-37 (2.5-2.6)
533-35 (2.3-2.5)
1031-32 (2.2-2.3)
1529-30 (2.0-2.1)
2026-28 (1.8-2.0)
(1)Vacuum hose connected at pressure regulator