Intermittent no start

If the security light isn't staying on, then chances are it isn't related to the anti theft system. What you need to do is check for spark and fuel to the engine. When it doesn't start, see if it does start for a couple seconds using starting fluid. If it does and then stalls, we know it's a fuel related issue. If it doesn't, then it's likely related to the ignition system.

Here is a link that may help. Take a look through it and let me know if it helps.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Let me know if that helps and what happens if you use starting fluid.

Joe