Stocks continued to slump in early-afternoon trading Tuesday, a day after the market’s shellacking. Auto-related stocks particularly paced the downside. The S&P 500 was off 0.1% following Monday’s 1.5% beating. But the SmallCap S&P 600 rose nearly 0.2%. Oddly, the Russell 2000 was down 2.6%. The Dow industrials fell 0.4% despite a nearly 2% advance by Wal-Mart Stores (WMT) while the Nasdaq slid nearly 0.3%.