I can be an app, your rom, your battery that is damaged or some other hardware failure. Hard to tell.
Try a different rom, don't install any apps, change your battery.
Samsung Galaxy S 4 I9505 | WanamLite v3.0
Samsung Galaxy S II I9100 : AOKP 4.2.1
HTC Touch Pro2 | ROM: Valkyrie 6.5.23115TR2.5
HTC HD2 | DarkStone1337 [FroyoStone Sense - V3.2]
HTC Desire : Oxygen v2.1.3