Custom query with query_posts doesn’t show post without certain meta_key

Well, you can’t sort by field that isn’t there. You can modify query conditionally only in those categories which have that field and let default query work in rest.

It would be something like:

if( is_category('abs') )
    query_posts(
    array_merge(
    array('orderby' => 'meta_value', 
                  'meta_key' => 'field_order', 
                  'order' => 'Desc' ),
    $wp_query->query
        )
    );