Yamamoto finished the season strongly with three consecutive finishes, an upturn in form after retiring from his first four Grands Prix. He also set the seventh fastest lap and second fastest middle sector during the 2006 Brazilian Grand Prix. However, this was not enough to prevent him losing out to Anthony Davidson in the race for the second Super Aguri race drive in 2007. However, he remained as a test driver at Super Aguri. This was combined with him competing in the 2007 GP2 Series season with BCN Competicion.