He stayed in the V6 Eurocup in 2004, and was also set to drive in the Le Mans Endurance Series before complications prevented him from doing so.
However, at the last minute, he was replaced by Adam Carroll who will now partner ex-Jordan Grand Prix driver Giorgio Pantano.
He finished third in the Le Mans Endurance Series LMP1 championship for Zytek, winning the 1000 km Nürburgring.
In 2005 he won the Monterey Sports Car Championships, the final race of the season in the ALMS.
He also represented Japan in the A1 Grand Prix series for the first time at Eastern Creek in November 2005, and was lucky to escape with only a concussion after a spectacular crash in which the engine separated from the chassis.