HC-05 with ELM327 mini OBD2 Bluetooth adapter connection problem
I faced a similar problem when working with HC-05 module with an Android terminal application and connection was lost after some time and many it was just not able to connect.
Upon some hit and trials I found that it was just an power issue with HC-05 and as soon as I tried it out by reducing load on HC-05 by connecting it alone on 5V supply from Arduino and switching others to a 3V supply it worked like butter and I didn't faced any problem till now.

This worked for me try this out.