Keith,
If you're talking about the M-Dash and N-dash showing up in your document, it may be because of automatic character substitution being allowed. It will seem erratic because it's based on the location of the cursor when you type the '-' key. It will enter a dash, ndash or mdash based on what type of character is just before it meaning letter, number or space. You can also cycle through them by repeatedly hitting the '-' key. Since there isn't an ASCII character for those two, I assume they're being saved as entities.
If this is the issue, you can turn it off by either the DCF file for the doctype, or by remapping the '-' key in your init ACL file. It depends on the scope you want to address.
Hope this helps,
Bob