My car it will not start my car unless I hold the key fob?

I suspect you are going to have to replace it. If the battery is good and the only way it is recognized is by holding it to the start button, then there is normally a defect in the key. Do you have another key that you can see if it starts normally?

If not, we need to check for codes because there could be an antenna issue.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

We could have an issue with the antenna but we should have codes for that.

Basically when you hold the key to the button the immobilizer senses that the correct key is within that close proximity and it overrides any possible issue. This is a programmed safety feature so that even if the battery is weak or drained, you are not strained somewhere.

I am attaching the process for replacing the interior antenna if this proves out to be the issue.