Troubles in Detroit continued to rock Wall Street yesterday as a second rating agency downgraded the debt of Ford Motor Company, a move that sent stocks skidding through another ugly session. Moody's Investors Service cutting the automaker's $175 billion in bonds yesterday to just above so-called junk status. The second ratings cut in a week for the second-largest carmaker, the news caught stock investors off-guard, and traders said it was the reason behind the Dow Jones industrial average's 110.77 point drop to 10,189.48, a 1.08 percent decline. The broader market averages declined as well, with the Standard & Poor's 500 dropping 11.75 points to 1,159.36, a 1 percent decline. Ford's stock dropped 29 cents to $9.35. Yesterday's downgrade was another bruise to the hedge fund community, which owns substantial amounts of bonds and complex derivatives in Ford and its troubled rival, General Motors.