Mysterious Car Bluetooth Dropouts Solved Before Your Very Eyes :-)
Although I found the page somewhere on the iMore forum yesterday which gave me the idea for the solution, and I *know* I posted there, today I can't find the same thread. Nonetheless what I experienced and how I solved it might help some of you.
After the Bluetooth signal from my iPhone 5 kept disappearing and quickly reappearing many times during each drive of my brand new Ford Fusion Energi, I was frustrated and annoyed. That the car has a factory-installed Sony sound system made it even more surprising and unexpected. The phone is in excellent shape, and was replaced by Apple with an Apple certified one around 1 1/2 years ago.
In the Ford Fusion Energi with the Sony sound system, there would be gaps in the audio playback of between 1/2 second and (sometimes) 2 seconds. The phone's app source didn't matter. It could have been Pandora, Apple's own music player, the Audible spoken word player, or the Cesium or Ecoute music player apps. That shouldn't have been happening on a car with an MSRP north of $38K, connected to a phone with an original retail value of $750.
I had just returned my leased 2013 Prius which didn't have this problem using the same software (iOS 9.3.x or 8.x). The Bluetooth in my long-gone 2010 Prius was equally flawless with an iPhone 3GS and an iPhone 5.
So somewhere on the now-lost iMore fora thread was a post by someone who suggested two things as potential solutions. The first was to disable Siri. That's the solution which worked, and I'm going with it. Although that also disables voice commands in a car when you can be cited for having the phone in your hands, and it is a significant reduction in the features promised to be usable by Apple.
The other workaround suggested to solve the problem was to disable the automatic program voice announcements pause of the iPhone's Map program. To disable the voice pause you need to launch the Maps program and fiddle with its settings.
So, today for the first time since I took possession of the car three weeks ago, I had uninterrupted Bluetooth broadcasts and playback. Creative alpha wave bliss is what that is.