WASHINGTON (AFX) - The economy may be approaching its speed limit, and inflation pressures could emerge if the Fed isn't vigilant, Chicago Federal Reserve President Michael Moscow said Tuesday.'With the unemployment rate currently at 4.7% and capacity utilization near its long-run average, it is important to ask how much slack remains in the economy,' Moskow said in prepared remarks to the University of Chicago Graduate School of Business. Moskow's remarks are almost identical to a speech he gave in February. He repeated a warning that overnight interest rates may need to be tweaked some more to keep inflation expectations from rising. This story was supplied by MarketWatch. For further information see www.marketwatch.com.