Do you have these problems with Plexamp on Android Auto?
Plexamp always picks up where it left off playing the song I was listening to, but more often than not when I try to get to the home Plexamp screen on AA I can't - it will just show the Downloaded screen and an empty playlist. Killing Plexamp on my phone will almost always fix this - it automatically opens again, resumes the song, and the home screen and my libraries are available. Does this happen to others?
A second issue I have is that the highlighted selection always jumps to shuffle and I have to move it back. For instance, I select an artist and an album, I highlight the back button to go to a different album (I have to do this all with a controller in my car as it doesn't have a touchscreen) it will jump back to highlight shuffle. Does this happen to everyone who doesn't have a touchscreen? I assume it works normally if you have a touchscreen