I've replaced fuel filterand the fuel pump and the spark plugs

Have u checked the cadeletic converter. It can do funny things

You describe a failing fuel pump. The fact he had it changed 3 times tells me the quality of the pumps was not great, or there is a problem with venting or something else.
If he did not change the fuel filter the pump would fail quickly. Since you changed the filter the next pump may last a long time.
A quality brand makes a big difference in this component.

could have clogged fuel injectors,could have intake leak,bad faulty fuel injector,weak or failing fuel pump, bad spark plug or bad ignition coil, many things will cause vechicle stall out at junctions.

Your testing so far seems to exonerate components #1 to #5, and #13.
Since you've already replaced a number of parts to address the problem, I thought I should try to be comprehensive:

Priority Action Part Type Cause
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 Starter Solenoid - Starter Solenoid Faulty.
5 Inspect Starter Motor - Starter Motor Faulty.
6 Inspect Wireset - Worn or Damaged Spark Plug Wires.
7 Inspect Ignition Coil - 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, or burned rotor contacts.
11 Inspect Fuel Tank - Fuel Tank Empty.
12 Inspect Carburetor - Worn, Faulty or Damaged Carburetor.
13 Inspect Fuel Pump - Faulty Fuel Pump.
14 Inspect Fuel Pump Strainer - Fuel Pump Strainer Clogged.
15 Inspect Fuel Filter - Fuel Filter Clogged.
16 Inspect Air Filter - Air Filter Clogged.
17 Inspect Fuel Injectors - Fuel Injectors Clogged/Inoperative
18 Inspect/Test PCM - Powertrain Control Module (Computer) defective - sending incorrect ignition/timing signals to fuel injectors
19 Inspect Fuel Rail - Fuel Rail leaking/broken causing inadequate/low fuel pressure.

Use a HEI (High Energy Ignition) tester to see if you have spark to your sprak plugs - if not, suspect Ignition Coil, Distributor Cap, or Distributor Rotor.

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.

Check for voltage at the plug, 12volts. Also check with a noid light when it is acting up. Wires tend to break right at the plug. check this to include pulling the wire and the plug. I've had them hanging together with just a strand or two and when it heats up it doesn't make a very good connection.

MISFIRE ON CYLINDER 6 COULD BE FAULTY SPARK PLUG OR BAD IGNITION COIL OVER THE SPARK PLUG,YOU COULD HAVE HAVE CLOGGED FUEL INJECTOR.CLEAN ALL FUEL INJECTORS USING A CAN OF SEAFOAM TO 3/4 TO FULL TANK OF GAS SEE IF NUMBER 6 MISFIRE CLEAR UP, IF NOT COIL OR FUEL INJECTOR COULD BE AT FAULT.ALSO CHANGE 6 SPARK PLUG FIRST.BEFORE BUYING NEW COIL OR FUEL INJECTOR THAT WAY YOU KNOW PLUG NOT THE PROBLEM.

Spark plug wires will last 20 years in most cases
Spark plugs never fail to fire,they are replaced at 60,000 miles,
not over 3 years,regardless of milage.
Injector cleaner is useless and a waste of money.
How would 10 oz in a 15 gallon fuel tank fix anything
common sense.

Now you diagnose your drivability issue
Retrieve the code,if any, that set the check light,
proceed from there.

You stated a cylinder misfire,so you already know your problem
Coil pack, Coil -On-Plug,what ever you have on your vehicle.

The stalling is another issue,unless the misfire is so bad that it
spikes the computer,comes back on the TPS Sensor and the vehicle
goes into failsafe and shuts off. Still bad coil issues.

could bea few things. Excessive moisure, low fuel pressure, Faulty coil pack, spark plugs gap or wires. Have you changed any of those at all? Let me know

change plugs wires also .fill gas tank up put prestone or gum out fuel injector cleaner.drive car around several miles.give injector cleaner time to clean out injectors.wait until engine cool .change fuel filter.relief fuel pressure before changing fuel filter.