CHARLOTTE, N.C. -- NASCAR fined Kurt Busch $50,000 on Friday for his poor behavior during the Sprint Cup finale last weekend at Homestead-Miami Speedway.

NASCAR cited both an obscene gesture Busch made inside his car and him being verbally abusive to a reporter in fining the 2004 Cup champion.

"Kurt Busch showed disrespect toward a media member, an incident that followed similar inappropriate media confrontations earlier in the season," NASCAR said in a statement announcing the penalty.

Busch had a transmission problem early in Sunday's race that sent his Penske Racing Dodge to the garage. His in-car camera caught him making an obscene gesture during that time.  While his team made repairs, Busch waited to be interviewed by an ESPN reporter, and a fan videotaped Busch being verbally abusive while waiting to go live. That video was posted on YouTube, and both Penske officials and Busch have apologized in separate statements for his behavior.

"Unfortunately, our result in the season-ending race at Homestead on Sunday was not what we had hoped for as a team," he said. "In my frustration with the loss of my transmission early in the race, I let my emotions get the better of me. I regret having done this and apologize to the sponsors of Penske Racing, to NASCAR, its fans, to the media and in particular, Dr. Jerry Punch."

Penske officials said earlier this week that Busch's "inappropriate actions" were being reviewed internally.

"These actions do not represent Penske Racing and are inconsistent with the company's standards for behavior, respect for others and professionalism," the team said in a statement.

The penalty comes just days after Busch crew chief Steve Addington quit the team, and three weeks to the day that Busch's younger brother, Kyle, intentionally wrecked Ron Hornaday Jr. under caution in a Truck Series race.

NASCAR suspended Kyle Busch for the remainder of the weekend at Texas -- he was entered in both the Nationwide and Cup events -- and fined him $50,000 for the Hornaday wreck. He then spent the next week fighting to keep his seat with Joe Gibbs Racing because sponsor M&M's was embarrassed by his actions.

He lost all composure during a race at Richmond in May, when he berated his team and Penske management over his in-car radio.

Busch's sponsor Shell/Pennzoil said in a statement it was disappointed with the driver.

"Shell and Pennzoil are disappointed with recent actions by driver, Kurt Busch, at the final race of the 2011 NASCAR Sprint Cup Series race season," the company said in a statement. "His actions are in no way consistent with the way we want our brands represented and we have expressed our disappointment and concerns directly to Penske Racing."

At the same track in September, he had an angry post-race confrontation on pit road with another reporter, then continued the argument before his formal news conference. He also ripped apart another reporter's papers the same evening.

Although he beat Johnson at Dover in the third Chase race, he faded as rumors spread Addington was bolting.

Busch wrecked at Talladega, ran out of gas while leading at Phoenix and had the transmission problem at Homestead. He ended the season 11th in the final standings. Kyle Busch, who opened the Chase tied for the top seed, finished 12th. Neither Busch brother will be part of the formal ceremony at next week's banquet in Las Vegas -- their hometown.

It's not clear what action, if any, team owner Roger Penske will take against Kurt Busch. He's remained largely silent when Busch has acted out in the past, but the emergence of teammate Brad Keselowski has given Penske reason not to tolerate Busch's behavior any longer.

Keselowski, in his second Cup season, won three races this season and finished fifth in the final standings. He's also become a fan favorite for his outspokenness -- candor that proved last week can get him in trouble: Keselowski was fined $25,000 by NASCAR for comments critical of electronic fuel injection.