I have a 2002 chevy S10 4.3 6 cyclinder. I have replaced the fuel pump, battery, coil, spark plugs, spark plug wires, fuel pressure regulator. I attempted to use staring fluid and no luck. This truck won't start

Have you done basic troubleshooting? Spark at plugs? Fuel pressure? Compression?

Chevy 2500HD No Start No Spark No Fuel Cranks OK
Testing !!!

LOOK ON THE FUEL INJECTORS RAIL YOU SHOULD SEE A BLACK CAP THAT LOOK LIKE A TIRE AIR PRESSURE STEM REMOVE THE CAP AND FUEL PRESSURE REGULATOR IS THERE

You need to check the basics of combustion; Is there spark at the plug wires? Do the fuel injectors receive the pulse to fire, from the ecu? Does the fuel pump turn on for a second, when the ignition is initially turned on? All of these problems I have mentioned are related to the ecu being faulty.

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.

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 Coil - Ignition -- 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 Relay - Fuel Pump ----- 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.

check valve adjustment on #5, is cam lobe worn?

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 Coil - Ignition 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 Relay - Fuel Pumpat 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.

Looks like you've covered the basics, make sure the firing order is correct with your spark plug wire replacement. Hope this diagram helps.

1 Inspect Choke Thermostat Stuck or Improperly Functioning Choke Thermostat. 2 Inspect Fuel Filter Clogged or Dirty Fuel Filter. 3 Inspect Relay - Fuel Pumpat Faulty Fuel Pump Relay. 4 Inspect Fuel Injector Pressure Regulator Faulty Fuel Injector Pressure Regulator. 5 Inspect Fuel Pump Low Fuel Pressure. 6 Inspect Engine Control Computer Incorrect Operating Information Being Delivered and Sent From The EEC. 7 Inspect Fuel Pump Strainer Clogged or Dirty Fuel Pump Strainerat this is a list of things to check as u have a starting issue this should help u find the problem
1 Inspect Ignition Switch Improperly Connected or Faulty Ignition Switch. 2 Inspect Battery Battery Discharged or Faulty. 3 Inspect Battery Cable Coroded, Broken, Shorted or Poorly Connected Battery Cable. 4 Inspect Solenoid Switch Starter Solenoid Switch Faulty. 5 Inspect Starter Starter Motor Faulty. 6 Inspect Wireset Worn or Damaged Spark Plug Wires. 7 Inspect Coil -Ignition- Faulty Ignition Coil. 8 Inspect Distributor Cap Loose, Cracked or Worn Distributor Cap. 9 Inspect Spark Plug Incorrectly Gapped or Fouled Spark Plug(s). 10 Inspect Distributor Cap and Rotor Kit Loose, Cracked or Worn Distributor Cap. 11 Inspect Fuel Tank Fuel Tank Empty. 12 Inspect Carburetor Worn, Faulty or Damaged Carburetor. 13 Inspect Fuel Pump Faulty Fuel Pump.