FORT WORTH, Texas -- Winston Cup champion Tony Stewart's car was impounded Friday because it didn't meet specifications, a punishment never before handed out by NASCAR.

Stewart, known as the bad boy of the sport, was forced to use his backup car at the opening practice for Sunday's Samsung/Radio Shack 500 at Texas Motor Speedway.

Moving into the backup prepared hurriedly by his team, Stewart qualified 22nd in the 43-car field.

"The cars all look the same from where I'm sitting," Stewart said. "I've got three things I'm in control of: a steering wheel, the shifter and the pedals. All our cars are good, whether they're primary or a backup."

Trying to match the right car with the track, Stewart had never used this particular vehicle. But the Joe Gibbs Racing entry failed inspection because it didn't meet the exact specifications for "the area around the back of the car, back window to back deck," NASCAR president Mike Helton said.

"We decided to impound the car instead of letting them cut it up and try to fix it, if they wanted to," Helton said.

Helton said the car will be sent to the sanctioning body's new research and development facility in Concord, N.C., for further study.

NASCAR had never impounded the entire car of a Winston Cup driver. Stewart's team could face other penalties or fines, but losing the primary car was damaging enough.

Third in the points chase

Six races into the 2003 season, Stewart is off to his best start ever, ranking third in points. It was unclear when or if he would get the car back.

"This was as big a shock to me as it was to the people at NASCAR," said Stewart's crew chief, Greg Zipadelli. "There's a measurement between the offset of the decklid and the roof, and it wasn't exactly where it needed to be."

Zipadelli said he was disappointed with the Gibbs crewmen who put the car together at the race shop in Huntersville, N.C., "because it's a measurement that's pretty cut and dry."

"We've got to work a little harder now to overcome this deal. We'll race well, but this has got everyone kind of down. It's a distraction is the biggest thing. But it's self-inflicted, so we've got no one to blame but ourselves."

Zipadelli said the team was having another car trucked in from Huntersville to serve as a backup for the rest of the weekend.

The Winston Cup inspection process has been more stringent this season with the adoption of a set of templates intended to fit all four makes of cars competing in NASCAR's top series.

All the cars must exactly fit 18 of 32 steel templates used during technical inspections. Until this season, there was a completely different set of templates for each make.

NASCAR had never impounded an entire Winston Cup car, although it often seizes illegal or unapproved parts and displays them for other teams to see.

This time, it is Stewart's race car that was on display next to the NASCAR hauler.

Asked if that was an indication to other teams how seriously NASCAR views this violation, Helton said, "The parts and pieces we confiscate get tagged and are left out on the back of our truck for people to look at. I'd say this fits that scenario."

Stewart has been in trouble with NASCAR for on- and off-track problems. He finished the last two seasons on probation, last year becoming the first NASCAR driver to win a title while on probation.

He was fined $60,000 and had to undergo anger management counseling after he punched a photographer at the Brickyard 400 in August. He also was accused of shoving a worker and pushing a fan.