podcast playbacks stop and start: iPhone 4S & VW GLI Autobahn

when i listen to a podcast on my iPhone 4S in my 2012 VW GLI the playback starts and stops. i can see the play button on the car touch screen go from the play arrow to pause button @ irregular intervals. my phone is paired via bluetooth. all other functions work just fine, connecting immediately, voice commands, contact lists, etc. so far i have not noticed any issues with music playback, only with spoken word, (like "the moth," "this american life," etc.). the car system is the fender without navigation. it seems to be getting worse, so podcasts are almost unlistenable. any suggestions? and thanks!