Not getting fuel to no. 2 injector and no. 3 injector but one and four has plenty

Bad driver in ECM/PCM

Check the injector fuse.

have you performed a compression test?a cylinder with low or no compression will cause a misfire

For 1999 Buick LeSabre - but you took #1 off the list, so here's the whole "failure to start" list:

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 Starter Relay Faulty Starter Starter Relay
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 Motor Faulty Starter Motor
15 Inspect Fuel Injector Dirty or Worn Fuel Injectors.
16 Inspect Fuel Pump Strainer Clogged or Dirty Fuel Pump Strainer
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 Rotor Distributor Rotor broken, burned contacts, or loose
21 Inspect Distributor Worn, Loose, or Incorrectly Installed Distributor.

Priority Action Part Type Cause
1 Inspect Catalytic Converter Clogged or Faulty Catalytic Converter.
2 Inspect Piston Ring Set Worn or Broken Piston Rings.
3 Inspect Distributor Worn, Damaged or Faulty Distributor.
4 Inspect Distributor cap/rotor Worn, Burned contacts

Priority Action Part Type Cause 1 Inspect EGR Valve Improperly Functioning or Faulty EGR Valve. 2 Inspect Fuel Filter Clogged or Dirty Fuel Filter. 2 Inspect Fuel Injector Dirty or Worn Fuel Injectors. 3 Inspect Radiator Cooling at System Clogged. 4 Inspect Timing Specification Incorrect Ignition Timing. 6 Inspect Coil -Ignition- Faulty Ignition Coil.

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.

Hello: Remove the fuel rail with the injectors attached and wires connected. Disable the ignition system. Have helper turn engine over, see if 3 & 4 injector are firing properly, some times the fuel rail gets trash in it and 3 & 4 do not get enough fuel. Remove the injectors from the fuel rail and see if the inlet to the injector has trash in it.

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.

Check all the fuses,and check the fuel pump relay,if this checks out o k,See if there is fuel pressure at the fuel injectors,if there is,then the injectors are not pulsing.The cause of this is the pick up coil in the distributor,but replace the distributor as a whole,this has all the components in the distributor,That control the fire,and the pulse to the injectors,A used one might be more economical sound money wise.

I would check to see if the injectors are firing. Most injectors are a pulsing ground type. So you can use a test light to check them.