Lap Timer/App Hang

Samsung Galaxy S5 (T-Mobile), Track Addict 3.7

I've been having problems with the TrackAddict app sporadically hanging for 5-6 second periods, evidenced by the lap timer getting stuck, then resuming several seconds later (it doesn't lose time, just hangs for a period). I suspect this is also the cause of some intermittent GPS and OBD dropouts I've been experiencing in the recorded data.

I'm using a OBD-II connector, recording video in 1080p, and controlling a GoPro Session. Maybe it's just too much for the camera to handle, or maybe another app on the phone is hogging CPU. Any suggestions on how to diagnose the problem? I'm a Windows software developer, but don't know much about the Android environment.

It looks like most of my problems were due to a defective SD card. I also moved to using a dedicated phone that's not my 'daily driver'. After that, the performance seems great.