As JAYDBPR said, check the bolt holding the battery ground cable to the chassis. Mine looked pristine from the top, but the section of threads that actually makes contact with the body were terribly rusted.
I replaced the bolt, and cleaned up the threads on the car. My car wasn't dying while driving, but it did fix a whole lot of little things.
2009 PBM GT
Under the Knife Again
Wiseco Pistons, K1 Rods, Johnson Lifters, BLP Keep Hatin' PDS Cam, Roto-Fab, BLP Ported Intake and Throttle Body, Kooks 1-7/8 long tubes, XForce Varex Catback, ZL1 Converter, Camaro Trans Pan/Filter, GXP Brembos
Breyton GTS-AV Wheels, 6k HIDs, Holden Steering Wheel and Paddle Shifters, Eibach Springs, 35% Tint
Tuned by Day Tuning