I have some more information:
- Tried wake lock and keep active
- The icon is always visible in the notification bar
- I tried removing all sms messages
- Regarding os and apps; i run not many apps, its actually basic CM11 + gapps, and also its basically identical to my nexus s setup.
- I don't have additional task managers and i don't expect apps to get killed because there is plenty of memory available
- I tried creating the hci log but this does not work for some reason: when i tick the create hci log the car doesn't connect at all any more, i restarted the phone, and also toggled bluetooth and enabling it; no success. Also when i first connect without logging, and then when the connection is established tick the log it immediatly disconnect. I will sent you the logs that i have but i don't expect them to be very useful.