General Motors top in-house market researcher has forecast a 3% fall in US vehicle industry sales, largely because no-interest loans coaxed many consumers into buying cars and truckers earlier than they intended, Reuters reported. Reuters quoted GM head of market analysis Paul Ballew as saying that the incentives, introduced by car makers to spur sales after the September 11, 2001 terrorist attacks, "will end up costing (the industry) 300,000 to 400,000 units" in 2003.