A judge approved a statewide class-action suit accusing Ford Motor Co. of concealing ignition problems in 2 million vehicles prone to stalling. Over Ford's objections, Alameda County Superior Court Judge Michael Ballachey allowed plaintiffs' lawyers to expand their suit into a class action on behalf of all Californians who bought Ford vehicles from model years 1983 through 1995 with a particular ignition mounting. The vehicles had a thick film ignition module, or TFI, mounted close to the engine where it was subject to high temperatures. The lawsuit contends Ford knew that all TFI-equipped vehicles were vulnerable to stalls at high speeds and that the problem continued for some models through the end of the 1995 model year. The company denies the allegations and, earlier Thursday, urged the National Highway Transportation Safety Administration to speed up a review the agency began last week.