No.
If you sync everything, the everything would be on your ipod. Everything would include playlists.
You asked how to delete music from the ipod. I responded "the sync process". If you do not select it to sync then it will be deleted when you sync.
If you go to the ipods music tab in itunes (with ipod attached), then you can select specific playlists,etc to sync.
Have you looked at the manual?