[treblig]

I guess it has never ran right??

If so:
If it runs then just stops that means everything works to a degree. Timing, O2’s crap like that will not stop the motor. I will cause it to run rich or lean, idle fast or slow. With moving components (cam, piston,crank,valaves) causes movement of wires, builds up heat and so forth this is causing it to quit on you.

This could be one or two problems or even both. Fuel flow or wiring.
1. The easiest thing to check first is fuel flow. Check the fuel flow / fuel pump. Go as far to the intake system as possible ( at the injector or carb. ) no flow then work yourself back until you get a consent flow. You need to run the flow test longer then the engine will idle. Don’t trust any gages, do it manually.
Check color of fuel filter dirt
New or used tank, rust inside?
Fuel lines smooth bends no kinks, clamps. If you have braded lines make sure you can see day light. On your pickup tube I’ve even seen where the screen got sucked into the line.

If the flow is constant then you an electrical problem.

1. On fiberglass cars 90% is due to incorrect ground or poor ground wires. This will really mess up any relay you have. I fought this for two months! What will happen here is,,, the car will start then stop. You turn the key to start it again and it just clicks because you lost your flow. Then the next day it will run.

2. Loose wire somewhere. Start by elemating all unnecessary system by pulling the fuses. All you need are systems that make the motor go. If this is your problem then plug each system in by it’s self. When the motor dies then you have and short, broken wire within that system.

3. OR, when the motor is running take a no-bounce hammer and tap your electrical components. You could have a bad solder joint, cracked board. Another trick is to get a hair dryer and put heat to your system. Heat will cause expansion causing everything to grow.

I know this is a lot but if you take it to a shop their just going to replace each item and charge you for one or ten items. Plus you will learn more about your car in case you have any road side issues. Like you do with Chevy’s.