Noob here, go easy on me.... 2002 WRX, 4 cylinder. The car jump starts and runs fine but while running the gauges and radio go dead, then jump back on intermitently. Battery charges a little after a long run. Battery terminals are clean. So this could be a short, a bad battery (It's only a couple years old), or a bad alternator (Original). Any thoughts on how to proceed before I start replacing things. Thanks