Get an app called Watch Dog Lite and tap preferences, check single alert after setting the threshold for alert in the setting above it
What it does is monitor what's using cpu, thus causing heat and battery drain. It's priceless for finding rogue apps and services.
It's also free I've got mine set to alert above 40% so anything that goes rogue well set off an alert. I can kill stuff from the alert or choose to ignore or even white list it , for things such as Android System that spike every now and then but that is normal behavior, so it won't alert again. You might find a higher threshold causes less alerts if you're trying to track down a problem.
Hope that helps
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