My car pops out of 4th gear while driving

This could be shifter related issue, so I am attaching the info below on this.

However, this can also be a clutch issue or even a synchro issue inside the transmission.

So we need to start with running through this this info and we can start with this guide:

https://www.2carpros.com/articles/clutch-symptoms

Once we start to cross these things off the list, please refer to the info from the manual below on the shift linkage and shifter.

Let me know what you find and what questions you have.

Thanks