Driven by a re-energized Japanese economy and aided by a weakening yen, Toyota Motor Corp. and Honda Motor Co. Ltd. earn significantly more in the year ended March 31. Nissan Motor Co. Ltd. narrows its loss to $773 million from 1.7 billion. Toyota's profit surges 46% to $2.4 billion, while Honda's bottom line improves by 15% to $665.7 million. Toyota's performance comes despite selling 5% fewer vehicles. With some analysts predicting that the yen win fall from its current Yen 106/$1 to perhaps Yen 130/$1 by year end, 1996 should be even stronger.