ordering post by date

Hi guys
i am trying to display posts in order of date they are posted but ‘orderby=date’ dosent work…. also i tried ordering post by title but
order=ASC or DESC dosent work at all…..
here is my query posts code please help me

<?php query_posts($query_string . ‘&orderby=date&order=asc&posts_per_page=-1&category_name=car_news’); ?>