Isuzu has consolidated its US operations, the company said yesterday, by combining American Isuzu Motors Inc., distributor of sport utility vehicles and diesel engines, with parent company Isuzu Motors America Inc. as one organization called Isuzu Motors America (ISZA). The change, effective from April 1, means ISZA is now responsible for all Isuzu operations in the US except commercial truck sales and support. That operation, General Motors Isuzu Commercial Truck (GMICT), will operate as an independent unit.