Reader Zane C. writes: The president of Japan's sixth largest auto corporation has admitted to manipulating test data on fuel economy (mileage test data) for 625,000 total eK Wagon and eK Space models, as well as the Dayz and Dayz Roox models produced for Nissan Motors. The tests overstated fuel efficiency by 5 percent to 10 percent. The offending models have been taken off the market until the problem is fixed, and foreign markets are being investigated for similar violations. Upon the announcement of the manipulations, Mitsubishi's stock dropped 15% and it lost 1.2 billion dollars in market value. The company apologized for the deception and said that it is investigating the employees involved. According to Mitsubishi, it was Nissan's in-house testers that discovered the discrepancy between the cars' published fuel efficiency data, and their real-life results. The affected models are sold exclusively in Japan.