Why Advance Auto Parts Stock Plummeted Today

Advance Auto Parts will "beat" earnings this quarter -- but that's not what investors are worried about.Advance Auto Parts (AAP -7.08%) stock tumbled 7.3% through 1 p.m. ET Thursday, leaving investors wondering "what went wrong?"The auto parts retailer preannounced "highlights" from its Q2 earnings today, and the highlight-iest part of all was this: Q2 revenue that Wall Street predicted at $1.97 billion will definitely beat that number, and might rise as high as $2 billion. Advance Auto Parts Q2 earningsSo ...