I did the same, only for kicks, I ran general election of Obama/Biden v. Bachman/Ayotte. At General Election date, I was only at 47% in Utah, while Bachman was at 12%, with undecided 41%. After election, I picked up 30% of the undecided, given my advantage over Bachman was 77 to 23. I chalk that upto either a bug, or rather, people don't like their party's candidate and vote lesser of two evils at polls.