WASHINGTON (Feb. 1)—The National Highway Traffic Safety Administration has upgraded its investigation of 926,000 Ford Windstar minivans to an engineering analysis after receiving reports that a spring in the suspension system can break and puncture a tire. The agency is probing Windstars made from 1995-98. It has gathered 199 complaints of the front suspension coil breaking and causing tire punctures at highway speeds. No crashes, injuries or fatalities have been reported, a spokesman said. The agency also is investigating Volkswagen Jetta, Passat and Cabrio models—years 1993-2000—after receiving 31 complaints that the fuel tanks can be punctured from right rear tire blowouts. No reports of deaths or injuries have been filed with NHTSA.