i have a problem with my battery light coming on. it comes on at very random times, usually only when i mash the pedal to the floor. at first i thought it was a lose power wire from the alternator but i checked that and it's fine. when the light is on the engine has an erratic idle and all the lights in the car dim. if i rev the engine above 4 or 5k then the light goes off, sometimes it'll stay off other times is will go back on. any ideas? could this be a corroded ground?