95 Cutlass Supreme with stalling/turnover problems

My 95 Cutlass Supreme has been giving me problems. Last year, after sitting in the hot sun for a week, I drove it for about 15 minutes, going an average of 45mph and it stalled when I stopped at a red light. I restarted it and the car was fine. A few months later it stalled as I was about to go up a hill. Again, I restarted it and it was fine. In July, after sitting for a week again in the sun, I started the car, drove about 10 minutes at about 25mph and my car stalled. It would not restart. I took it to a garage and a technician worked on it for 3 days before replacing a computer that signals the fuel. The car has been fine ever since then, until yesterday. I drove it on an interstate at about 65mph for 45 minutes and parked. When I tried to restart it to move it, it would not restart. Does anyone have any idea what is wrong with my car? Any help would be greatly appreciated!

When you say "it would not restart", do you mean that the engine cranks and cranks (turn over) but would not run? Or It does not nothing and your hear a click or no click at all when you try to start it.

Turn on your headlights and try pressing the horn, if the headlights are bright and the horn is good and loud then, turn your ignition swith to ON position (just before cranking), put the transmission in Neutral and try starting the engine again to see if that works.

If your headlights are weak and horn is weak then try to jump start the vehicle or try to recharge the battery to full charge with a small battery charger/starter 120v type.

Follow the battery red cable from the battery and make sure the connections are tight. Mostly, with vehicle like this, they have a remote positive terminal on the side of the engine. Just follow the red cable wire from the positive terminal on the battery and it will connected with another cable with a nut and make sure it is tight and if not then tighten it.

I just went out and the car started again. It does this randomly. It will "crank" but not turn over. I tried to jump it last time it stalled and would not turn over but it did not help. I am paranoid it is going to stall in the middle of a busy highway!

you need to determine if you have spark and/or injector pulse when the car acts up. That will help us narrow down your problem. You will need a spark tester and a noid light set to determine if you have spark and injector pulse.

You may have a failing fuel pump. I have similar problem what you are describing and it fixed after I replaced the fuel pump.

However, on your vehicle, if it does not start again, it will be helpful to use a spark tester (get it a local automotive store). It has an alligator clip on one end to clip to a metal ground on your engine. Adjust the distance of the gap for your vehicle. Just disconnect one of your spark plug wire and connect it to this spark tester and then clip it to the metal ground. Start your engine and watch to see if there is a spark. If you got a spark then it could be fuel related. You can also use a fuel pressure tester available from autozone for rent and check for proper fuel pressure when the engine does not turn over.