The Exxon Corp, US, has landed in the dock again. This time the case it is facing is a suit filed by the Federal Trade Commission against its advertising which claims that its gasoline makes engines cleaner and reduces maintenance costs. The agency filed a complaint against Exxon calling for an administrative-law judge's order to force the company to produce scientific data to support its assertions. Consumer groups have been complaining against the claims made by oil companies about the benefits of high-octane gasoline.