The jury is still out on zero percent or "interest-free" financing as General Motors Corp. hailed it in its Keep America Rolling campaign, according to the Detroit Free Press. It undoubtedly spurred industry sales in October 2001 and in the months since, but many auto analysts and economists worry that automakers like GM have created a expectation with consumers that the industry can't continue to maintain.

"It was a good thing to do at the time. But

history hasn't yet sorted out what the long-term implications will be," said George Pipas, Ford Motor Co. sales analysis manager. "It's not

clear yet if we can throttle back on incentive spending. We tried to pull it back in May, and sales fell way off."

Rick Wagoner, GM's CEO, said the automaker has had to "redouble on cost reduction" to fund the higher incentives and would "welcome opportunities to get some pricing relief."