The General Motors Corp. is suspending its plans for virtually all new rear-wheel drive cars. The decision of the automaker is anchored on the impending threat of stricter fuel economy standards to be enforced by the federal government.

The largest automaker is bothered that the increasing mileage requirements will penalize the company for producing new versions of high-performance rear-wheelers. This is why GM is derailing the production of all but a few of its product lines.

The information about the change in plans of the auto giant was confirmed Wednesday by Bob Lutz, GM's product czar. The automaker did not give specifics about the plan. Moreover, the move could mean enthusiasts will never see a rear-wheel replacement for the Buick Lucerne and the Chevrolet Impala sedans or a small rear-drive Cadillac compact. The bumper as well as other distinct auto parts from the automaker could be facing extinction.

Nonetheless, the Chevy Camaro sports coupe, which is scheduled to be released next year along with the Pontiac G8 sedan, is still in the works. The vehicle is now being assembled by Holden, a GM subsidiary in Australia. Now, it seems, most of those plans are off. "It's too late to stop Camaro, but anything after that is questionable or on the bubble," said Lutz. "We'll decide on our rear-drive cars when the government decides on CO2 levels and CAFE regulations."

"It says they are making a commitment to maximizing fuel economy and maximizing fuel efficiency, and that makes sense," said Tom Libby, an analyst with the J.D. Power and Associates' Power Information Network.

The government administration intends to limit America's dependence on foreign oil 20 percent by 2017. Additionally, it intends to raise fuel economy standards to an average of four percent per year. That would bring cars to an average 34 mpg by 2017. The figure is up by 27.5 mpg today. Further, the Supreme Court ruled last week that the Environmental Protection Agency has the authority to regulate cars' carbon dioxide emissions.

Lutz has been a scathing critic of the Bush plan, arguing that such a mandate could add $5,000 to the average cost of vehicles. "It would bring the market to a standstill," he said in an interview during the New York Auto Show. "We've pushed the pause button. It's no longer full speed ahead."

The Ford Motor Co. spokesman Jim Cain said its plans already are heavy on vehicles that feature fuel-saving technologies, with no all-new rear-drive cars in the works. Ford, however, will continue producing new versions of its Mustang muscle car.

DaimlerChrysler AG's Chrysler Group, on the other hand, said last Wednesday it has no plans to back away from that market. The Auburn Hills automaker has plans to revive the Dodge Challenger muscle car at the end of next year.

"We've had some great success with that architecture," said Rick Deneau, Chrysler Group spokesman. Fuel economy regulations aren't "affecting plans for anything we're going forward with." Instead, he said, Chrysler will focus on improving technology on rear-wheel drives to make them more fuel-efficient. It does, however, plan to ramp up investment in fuel-sipping small vehicles.

"You arrive at a balanced product plan and then you work on the technology to deliver the fuel economy that isn't just what the government requires, but what consumers expect," said Colleen O'Connor, a Chrysler spokeswoman.