Ford Sales Fall, Chrysler Posts Gain  DETROIT (Reuters) - Ford Motor Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=F.N target=/stocks/quickinfo/fullquote"&gt;F.N&lt;/A&gt; on Wednesday  reported its sixth straight month of weaker vehicle sales,  prompting the second-largest U.S. automaker to further cut  production of cars and trucks, while Chrysler posted another  sales gain.