AVONDALE, Ariz. • Kyle Busch, contrite and remorseful, promised Friday to change his behavior after his road-rage incident at Texas, but it'll be a long road back.

Busch's primary Sprint Cup sponsor, Mars Inc., has warned Busch that it won't tolerate any more incidents by him, and team owner Joe Gibbs said the driver faces further punishment for wrecking Ron Hornaday Jr. under caution in last week's NASCAR truck series race. NASCAR suspended Busch from all on-track activity at Texas, fined him $50,000 and placed the driver on probation through the end of the year.

The crash led to a frantic week of behind-the-scenes negotiations with Joe Gibbs Racing and sponsors who viewed Busch's latest incident as the final straw for the polarizing driver. Although M&M's parent company has a contract with Gibbs Racing, company officials wrangled with Gibbs all week over whether they wanted Busch to represent the brand anymore. Ultimately, M&M's withdrew from the final two races of the year, but it'll be back next year and longtime Gibbs partner Interstate Batteries stepped up to be on Busch's No. 18 Toyota for the last two races.

"I'm sure I lost respect with my team, my sponsors, my peers, and I understand those consequences," Busch said Friday. "I understand my actions were uncalled for and disrespectful. I'm here to make sure I can continue in a positive manner and make sure everyone believes in me from this week forward."

With 104 victories in NASCAR's top three series, Busch opened the 10-race Chase for the Sprint Cup championship tied with Kevin Harvick as the top seed. But he stumbled through the first few races and never challenged for the title.