AVONDALE, Ariz. -- The puddle of oil dripping from the exhaust pipe and collecting under the right rear tire of the No. 18 Toyota in the garage area at Phoenix International Raceway told the entire story.

"No indication this time," Kyle Busch said. "Catastrophic engine failure."

Busch's return from a NASCAR-imposed sabbatical began with an engine failure even before he got up to speed Friday and another which ended his weekend with a 36th-place finish. After starting last in Sunday's Kobalt Tools 500, he worked his way through the field and into contention, only to slow with the tell-tale white smoke streaming from the rear of his car on Lap 187.

"Man, we were up to third," Busch said. "We battled up from the back of the pack and were running third between [Tony Stewart] and [Carl Edwards], the two championship contenders. We were right there with those guys, having our own story by battling for the win."

Instead, Busch turned into the garage area one lap later, climbed from the car and walked into his hauler as his crew popped the hood and peered down into the smoking engine compartment, trying to determine what might have gone wrong.

Owners Joe and J.D. Gibbs came over, along with several other Gibbs personnel, then walked away as the car was prepared to be lifted back into the hauler for the long trip back to North Carolina.

Friday's engine issue was blamed on what Busch termed "human error," as he left the garage without oil pressure and made one slow circle of the track in morning practice before coming back in. The bum motor was replaced with a fresh one, but that powerplant gave up the ghost just past the midway point Sunday.

It put an end to a tumultuous two weekends for Busch, who was parked at Texas after an incident with Ron Hornaday in the Truck race, and faced censure from his sponsors.

Despite his obvious disappointment in not being able to put a positive end to his visit to Arizona, Busch couldn't say enough kind things about his team.

"When you go through turmoil like this, all you can do is group together and pull through it and try to persevere and move on," Busch said. "We've got one more chance -- one more opportunity -- next week to win a race before the year is out to end it on a high note. I'm looking forward to next year with everything going on, and can't say enough about all these guys."

When asked about the new Phoenix surface, Busch said he was "on tip-toes the whole time" because it was so slick. But his mind was more on how his equipment let him down this time.

"It's terrible to have one [engine failure] in a weekend, let alone two," Busch said. "It's times like these where you feel like you're down in the dumps, and all you can do is try to pull together and move on through it.

"It's been a tough couple of weeks and all we can do is go to Homestead, ... win a race in the final outing and get some positive momentum into 2012."

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