These are the trouble shooting steps I would take.
- Make sure your phone and car software is up to date.
- clear all previous connections in your phone and your car's software and reconnect them as new
- Try to connect another phone to your car and see if it that phone disconnects randomy.
- Reset all settings in your phone back to default
- Back up your inofrmation and factory reset your phone.
- If all else fails, you can contact @SamsungAl and he could help you further
Like @waj94 said, it may just be your car's blutooth system but I would attempt these steps first just to make sure.
Hope this helps!