Can't really help you with this because I'm kind of having the same problem. I've got a brand new optima batt. and a "used" alternator. Have you changed the PCM at all though? Like bought a tuned PCM from zzp or 3800performance? That's when mine started to act funny. It might be because my cooling fan is on all the time since I have a 180* thermostat and the fans now kick on (and stay on) at 180*. And I'm running my AC all the time.