Before the bell: Stocks set to plunge on stimulus package, auto sector worries

U.S. stock markets were set to plunge at the open Tuesday morning after a three-day weekend. Investors may have wanted to forget last week's performance -- a 5.2 percent plunge in the Dow, a 4.8 percent drop in the S&P 500 and a 3.6 percent decline in the Nasdaq -- but three issues are weighing on their minds: The economic stimulus plan, auto industry woes, and economic crisis in Eastern Europe.

President Obama is reportedly going to sign into law a $787 billion economic stimulus package, which is said to be the most ambitious and massive plan in decades. It should help jump start the economy with infrastructure spending, tax breaks and more. It should also help create jobs and invigorate consumer spending. But Wall Street is concerned about the success of the plan, fearing it offers too little, too late.