It will try to turn over but dont hold?

Hello,

There are several reasons why an engine will crank but not start.
It could be due to a dirty throttle actuator or issue with the idle air control valve.
A clogged catalytic converter can also prevent the engine from starting.
If you have water in the fuel.
It can also happen for any electrical malfunction.

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

First you need to make sure you are getting spark to the plugs and also check for fuel.
With no spark the engine will crank but not start.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Also if the fuel pump stops working engine will not start either. Can you hear the fuel pump when turn the key to the on position?
You can also check for fuel pressure at the fuel rail by using a fuel pressure tester.
This vehicle should have 52-59 PSI of fuel pressure with the key on and engine off.

Here is a helpful guide:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please let me know of any questions.
Thank you.