Can I plug the fuel pressure connection assembly valve

I'm not familiar with Chevy's but a similar problem over the pond that is quite common is the EGR valve clogging up.
Not sure if this is relevant to a 2001 model but worth checking out.
Electricial cleaner is the best to use I have found.
hope this is of some help.

Could be a vac leak or a problem with the EGR valve among other things. Fuel pressure regulator comes to mind too.
If you did not use a GM pump I would recheck your fuel pressure.
If you have the vortec engine it takes at least 65psi of fuel pressure to make it run.

If your vehicle has one, and I think it does, check your EGR system. If the egr valve is full of carbon, it can be partially open, creating a vacuum leak. If the egr valve solenoid is bad, it could be opening the valve at the wrong time, also creating a vacuum leak. Unplug the egr vacuum hose, plug the open end of the hose and start it and see what it does. A picture of the egr is below.

Park your car in a safe and level place and open the hood.
Relieve the fuel system pressure: On 1995-1997 2.2L engine models, remove the fuel-pump relay from the fuse block located in the engine compartment, then start the engine and let it stall. On other models, wrap a shop rag around the Schrader valve located on the inlet fuel line of the fuel rail, right before the first fuel injector--the valve is similar to an air valve on a bicycle tire. Depress the small stem inside the valve using a small standard screwdriver to free the fuel from the line Disconnect the black, negative battery cable
Raise the rear of the vehicle using a floor jack and safely support it on two jack stands.

• Disconnect the filler hose form the tank by removing the hose clamp using a Phillips screwdriver or ratchet and socket. Remove the fuel tank shield using a ratchet and socket
• Support the fuel tank with the floor jack and remove the tank-mounting straps using a ratchet, ratchet extension and socket.
  
• Lower the tank carefully, just enough to disconnect the two fuel hoses and vapor hose from the sending unit/pump assembly on top of the fuel tank
  
• Press the lock tabs on the hoses connectors, and pull the hoses from the assembly fittings. Unplug the fuel-pump electrical connector and lower the tank to the floor.
  
• Remove the lock ring from the sending unit/pump assembly using a drift punch and hammer. Carefully rotate the lock ring tabs counterclockwise with the drift punch and hammer until the ring is free from the assembly.
  
• Lift the sending unit/pump assembly off the tank and out of the vehicle.
  

Install Fuel Pump

• Make sure the pump filter is in a horizontal position and does not interfere with the movement of the sending unit float arm, then install the sending unit/pump assembly into the tank using a new O-ring between the assembly and the tank.
  
• Secure the assembly by turning the locking ring clockwise with the drift punch and hammer.
  
• Raise the fuel tank enough to connect the fuel and vapor hoses and plug the pump electrical connector.
  
• Install the tank-mounting straps and tank shield, and connect the filler hose to the tank
  
• Lower the vehicle and install the fuel-pump relay.
  
• Connect the black, negative battery cableStart the engine and check for fuel leaks.
  

WARNING
When replacing the fuel pump in your Chevy Blazer, safety is your most important factor. Do not allow smoking near or around the car, and park away from appliances with open flames, such as water heaters and dryers.

REPLACE FUEL FILTER,CHECK FUEL PRESSURE, SHOULD BE SHOULD BE 9 - 13 PSI TBI FUEL INJECTION AND 55 - 61 PSI MFI FUEL INJECTION.WHEN YOU TURN ON IGNITION WITH ENGINE OFF.LET FUEL PRESSURE BUILD UP AT FUEL PRESSURE GAUGE TO CORRECT PRESSURE THEN TURN OFF IGNITION SWITCH. IF FUEL PRESSURE DROPS VERY FAST OR LEAK DOWN IN 10 MINUTES.YOUR FUEL PUMP CHECK VALVE FAULTY IS BAD.FUEL PUMP NEED REPLACING.BE SURE FUEL INJECTORS ARE CLEAN THEY WILL LEAK DOWN FLOOD ENGINE FOUL OUT SPARK PLUGS.

1999 Chevy Blazer 4.3L engine has an electronic EGR valve its in front of and below the intake manifold a cylinder looking part connected to a small wiring harness. It is bolted on with 2 10mm bolts alot of times a piece of carbon will get stuck in the pintle at the bottom of the EGR valve and will keep it open causing a large vacuum leak making it hard or impossible to start. Good luck.

Sounds like you have a fuel leak inside the intake. Remove the upper intake manifold. Cycle the key on and off and check for leaks from the fuel lines and pressure regulator.

It sounds like your fuel pressure reglator O-ring is leaking causing a delay in fuel pressure build up.

Hi have you checked fuel pressure or a fuel leak you should not be able to smell gas

Have you checked for spark? If yes, will it start if you spray carb cleaner in the intake?