just wanted to close my comment...replaced the alternator, got the battery good and charged and everything has been rock solid since. alternator change out was a piece of cake.
This issue sounds a lot like the one i'm having now. only voltage checks i have performed are on the battery...will do the shorting checks now. Would a shorted alternator cause the issues the OP was having? I tried to jump my truck just now and the battery wouldnt go over 10V. Kept smelling...
