I get the same thing. The app works fine if I'm listening through my headphones but has stuttering issues in my car. Haven't pinpointed it down at all. On my way home today I tried turning off my "location" to see if that had an impact and I still had stuttering problems. I turned that back on and pulled up OSMonitor to see if I could find a program hogging up too much CPU but I didn't see anything obvious and it was still stuttering while doing that. I then exited OSMonitor and then brought Poweramp up as the foreground app and didn't have trouble the next 10 minutes of my drive home. The screen turned off after a minute or so. I'll try different things over the next few days to see if I can pinpoint anything that might trigger it.