Advance Auto Parts is in trouble, and things are getting worse.Advance Auto Parts (AAP -16.50%) stock tumbled 15.8% through 10:35 a.m. ET after the company beat on sales but missed on earnings in its latest earnings release Thursday morning.Heading into the fiscal second-quarter results, analysts forecast the automotive parts retailer would earn $0.94 per share on just under $2.7 billion in sales in the period ended July 13. Advance Auto Parts nailed the sales target, but whiffed on profits, reporting just ...