Shavy

I had same issue with my iPhone 7 running on iOS 11, but when a pair my wife's iPhone 6 for audio streaming it works fine without any problem. Then I try to remove "My-Car" device from iPhone 7 and pair it again, but nothing changes. It still drops after 1-2 minutes. After that I go into Main Settings> Phone> Bluetooth and under registered devices choose iPhone 6 instead of my phone, and now my phone works fine without any issue. I think it may try to access contacts and for some reason disconnect Bluetooth because of compatibility thing