Tracking single audio tracks here, I lay down a guitar track, go back and lay down a vocal track, and on playback, they're out of synch by about a second. Tried recording both at the same time with two inputs, and they're still out of synch. In the latter case, it seems impossible to synch them perfectly no matter how much I try. Never ran into this before. Suggestions?

There is something definitely wrong with your set up. Please describe your sound card settings in sonar as this is where your problem is.
 
CJ