A slip of the tongue on TV cost Dale Earnhardt Jr. first place and $10,000, penalties imposed by an increasingly image-conscious NASCAR.

Earnhardt was docked 25 points yesterday in the Nextel Cup standings for using a vulgarity in an NBC interview after his victory at Talladega Superspeedway, dropping him to second place with seven races left in the season. He will appeal the point penalty.

Earnhardt still gets credit for the 14th victory of his career Sunday, and he has plenty of time to make up the deficit on new leader Kurt Busch, with up to 190 points available at each race.

Nonetheless, the punishment was criticized by Earnhardt’s team as too harsh, and it served as another example of how NASCAR is trying to shed its image as a sport that traces its roots to Good Ol’ Boys running moonshine through the hills of Georgia and the Carolinas.

“The popularity of this sport is based on colorful personalities and the fact that everyone can relate to these drivers and their emotions,” said Richie Gilmore, director of competition for Dale Earnhardt Inc. “Now it seems like that’s a detriment.”

Enjoying tremendous growth in mainstream popularity lately, the racing league landed a $2.8 billion television contract with NBC and Fox that began in 2001, and this season switched the sponsorship of its top division from cigarette-maker R.J. Reynold’s Winston brand to telecommunications giant Nextel.

As part of the whole scrubbing-up process NASCAR president Mike Helton told drivers in February to watch their language on radio and television. Less than a month later, he showed he meant it: Johnny Sauter lost 25 points for swearing during a radio interview after a Busch Series race in Las Vegas.

Ron Hornaday Jr. also was fined and lost 25 points for cursing during a live radio interview in June during a Busch race in Dover, Del.

“Helton made it clear … that we, as a family sport, were taking this very seriously and adhering to FCC guidelines,” NASCAR spokesman Mike Zizzo said. “The timing is unfortunate for Dale Jr., but NASCAR also made it clear to the competitors that we would police the last 10 races just like we did the first 26.”

It’s also part of an overall trend in sports and media, the most talked-about example being Janet Jackson’s “wardrobe malfunction” during her halftime performance at the Super Bowl. CBS was fined a record $550,000 by the FCC for Jackson’s breast-baring, and federal regulators cracked down on other objectionable content on TV and radio.

“I know the FCC has been hard on everybody since the Super Bowl mess, and we should have clean language. Mike Helton tells us to act like there are people from 8 to 80 that are watching us, but it’s tough,” driver Elliott Sadler said. “I can understand if we do something stupid on the race track to get penalized for it, because it might be putting somebody’s life in danger for doing something stupid, but as far as cussing or saying a bad word, maybe they should be a little lenient on that.”

Networks have installed delays of up to 10 seconds for some programming, and ABC’s “Monday Night Football” is using a 5-second delay this season. NBC does not give itself a chance to censor its NASCAR telecasts, though.

That’s why viewers in nearly 7 million homes were able to hear Earnhardt use a vulgarity when he was asked about the significance of his fifth victory at Talladega. Earnhardt told NBC, “It don’t mean s— right now. Daddy’s won here 10 times.”

Earnhardt’s father, easily the most popular driver of his era, was killed in a last-lap crash at the Daytona 500 in 2001.

Father and son won the adoration of millions in part because they built reputations for saying whatever they’re thinking. Some fans have criticized NASCAR for trying to turn its drivers into colorless automatons, who show little emotion and whose choreographed postrace celebrations revolve around repeated mentions of sponsors.

“This whole incident is going to force everyone in the sport to rethink showing any excitement in what should be a jubilant moment,” Gilmore said.

Little E wasn’t available for comment yesterday. On Sunday, he defended his use of colorful language.

“I hope they understand that it was in jubilation and I know me and those other guys that got fined let it slip, but it’s two different circumstances. I think that when you’re happy and joyous about something and it happens, I think it’s different than being angry and cursing in anger,” Earnhardt said.

“If anybody was offended by the four-letter word I said … I can’t imagine why they would have tuned into the race in the first place.”