Congressional tempers will be especially hot if the Treasury Department, in a report scheduled to be issued next month -- though it often is delayed -- again fails to formally label China as a currency manipulator, Vargo said.

Commerce Secretary Carlos Gutierrez will also be in China later this week to prepare for the April 11 Joint Committee on Commerce and Trade (JCCT) meeting. He will be proceeded by two other top U.S. officials -- Deputy U.S. Trade Representative Karan Bhatia and Commerce Undersecretary Franklin Lavin.

Gutierrez has warned the JCCT meeting could be called off if Beijing is not prepared to address a number of trade irritants, including piracy and counterfeiting of U.S. goods and continued obstacles to U.S. imports.

Washington also wants China to follow through on a promise to join the World Trade Organization's government procurement agreement, opening up new markets for many American companies.

Concrete action on those fronts could buy Beijing more time from Congress to gradually revalue its currency, said Cal Cohen, president of the Emergency Committee for American Trade.

"I believe what members are looking for is momentum ... China needs to demonstrate in some areas they are ready to move forward," Cohen said.