Pep Boys Stock Down After Earnings Miss  CHICAGO (Reuters) - Shares of auto parts retailer Pep  Boys-Manny, Moe   Jack &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=PBY.N target=/stocks/quickinfo/fullquote"&gt;PBY.N&lt;/A&gt; fell 10 percent on Thursday, a  day after it said earnings dropped 48 percent last quarter on  more struggles in its service operations, missing estimates.