Thanks for the info. I checked battery voltage :engine off=12.56 volts,engine on,accessories off=13.89volts.This is within spec I believe.I removed regulator assembly and found the brushes worn down to the little "R"that is stamped on them.Prehaps they are at their maximum wear limit and the cold ambient air temp that morning (45 degrees)caused intermittant contact til things warmed up.Just a theory since the car has run fine since.Iwill replace the regulator at my earliest convenience.138k miles is pretty good service from this unit!Thanks for the feedback,Dan