1992 chevy blazer 4.3 vortec engine 2w dr have change the fuel pump fuel filter spark plugs rotor in the distributing cap ignition coil.and still doesnt want to start only cranks but doesnt stay on.

Could be the EGR valve or the idle adjust valve. Check Engine light on? Any codes?

Check the plug wire from the ignition coil to the distributor cap.
If you haven't already, replace the distributor cap and rotor.
The GM Vortec's have issues with moisture getting inside the cap and rotor and causing problems.

I’m happy to help further over the phone at https://www.6ya.com/expert/jason_00b31cc8f593773a

You've already eliminated the spark plug & wireset, distributor cap & rotor.
Sounds like your car needs a tune-up, specifically, the PCV (positive crankcase ventilation) valve, and/of the EGR (Exhaust Gas Recirculation) valve.

Components checked/replaced during a tune-up are:
air filter
motor oil
motor oil filter
breather filter
fuel filter(s)
fuel strainer
PCV valve
EGR valve
spark plugs
spark plug wires
ECM or distributor cap & rotor
cabin air filter
transmission oil filter
transmission oil
engine coolant
check all vacuum hoses and lines

Troubleshooting the no-start condition - from the 1990 Mitsu Mighty Max Repair Manual:

Priority Action Part Type -- Cause
1 Inspect Battery -- Battery Discharged or Faulty.
2 Inspect Battery Cable -- Corroded, Broken, Shorted or Poorly Connected Battery Cable.
3 Inspect Distributor Cap -- Distributor Cap Cracked or Burned.
3 Inspect Fuel Filter -- Clogged or Dirty Fuel Filter.
5 Inspect Ignition Coil -- Faulty Ignition Coil.
6 Inspect Wireset -- Worn, Damaged or Faulty Spark Plug Wire(s).
7 Inspect Spark Plug -- Incorrectly Gapped or Fouled Spark Plug(s).
8 Inspect Starter -- Starter Motor Faulty.
9 Inspect Fuel Pump -- Low Fuel Pressure.
10 Inspect Solenoid Switch -- Faulty Starter Solenoid Switch.
11 Inspect Fuel Pump Relay -- Faulty Fuel Pump Relay.
12 Inspect Fuel Injector Pressure Regulator -- Faulty Fuel Injector Pressure Regulator.
13 Inspect Ignition Switch -- Improperly Connected or Faulty Ignition Switch.
14 Inspect Starter Drive -- Faulty Starter Drive.
15 Inspect Fuel Injector -- Dirty or Worn Fuel Injectors.
16 Inspect Fuel Pump Strainer -- Clogged or Dirty Fuel Pump Strainerat.
17 Inspect Engine Control Computer -- Incorrect Operating Information Being Delivered and Sent From The EEC.
18 Inspect Fuel Tank -- Fuel Tank Empty.
19 Inspect Carburetor -- Carburetor Flooded or Faulty Choke.
20 Inspect Distributor -- Worn, Loose, or Incorrectly Installed Distributor.

Hi, Ok you have confirmed that it's not a fuel problem. You need to check for spark. Pull the coil wire off of the coil(secondary lead-looks like a spark plug wire) Have some one crank it over and listen for a popping sound. IF yes, spark is at the coil, that means all ignition sensors are working. Next check for spark at ends of wires after cap. IF no replace cap and rotor. IF yes remove a couple spark plugs and check for fouling(wet, fuel etc...) IF yes replace or clean plugs and retest for starting. IF no spark is present at coil you need to scan computer and watch for rpm signal. IF no rpm signal, replace crankshaft sensor with OEM delco part. BIGGEST problem with these engines is Cap and Rotor burn out.

If your car have an alarm system, check for a hidden shut off switch, it must be re-set to start the engine again.
sammyc47

Check the fuel pressure at the fuel rail on top of the engine it should read a minimum of 30 psi if any lower replace the fuel pump, also if you smell a gas odor and the fuel pressure regulator looks wet with gas replace the pressure regulator before the fuel pump. This sounds like a fuel delivery issue.

Find the pressure test port (looks like a tire valve) on the fuel distribution rail over the injectors and place a can over the open end of the valve. Press the inner pin to release fuel into the can. If the pressure seems to fall rapidly, replace the fuel filter. Is the check engine light on? Rent a scanner, read any code(s), and pursue to repair(s). A bad crankshaft sensor or camshaft sensor can prevent the injectors from firing fuel into the engine.

Check for spark at a plug first. If none then its either the coil or ignition module. The module is located under the coil.

THE FUEL PUMP IS BAD.

if your losing fuel pressure after the pump runs the drain back valve in the pump has failed.

and i doubt that you are seeing enough fuel pressure to run a vortec engine.

low fuel pressure equals a non running vortec

Once you rule out some kind of ignition problems,; spark plugs and wires, ignition timing, distrib. cap & rotor, the cause may be low fuel pressure from a failing pump or clogged filter. Listen to the pump in the gas tank. If its been getting louder lately, have the pressure tested.