Mitsubishi Says It Tricked Fuel Mileage Tests On Some Cars

Carmaker Mitsubishi Motors says "improper conduct" resulted in 625,000 of its vehicles getting inflated gas mileage ratings, in a scandal that's centered on minicars made for Japan's market.

The cars in question are Mitsubishi's eK Wagon and eK Space, as well as the Nissan Dayz and Dayz Roox (which the industrial giant made for Nissan Motors). While the scandal seems to be limited to the Japanese domestic market, Mitsubishi says it is now investigating vehicles it made for overseas markets as well.

The fuel consumption cheat was uncovered by an internal inquiry that was sparked by Nissan's questions about irregularities in the cars' fuel consumption data.

Announcing its findings Wednesday, Mitsubishi said its employees manipulated the tires of cars that were being tested to provide official fuel statistics by improperly reducing the tires' running resistance.

"Following the announcement, shares in Mitsubishi tumbled," John Matthews tells our Newscast unit from Tokyo, "closing down more than 13 percent at the end of Tokyo trading."

All of the vehicles in question have very small engines — the powerplant in the eK Space, for instance, has a displacement of 40 cubic inches (659 cubic centimeters) and generates less than 50 horsepower, according to the Automobile Catalog site. The car is less than 5 feet wide; its gas tank holds a little less than 8 U.S. gallons.