Break of the Race: Jimmie Johnson

HAMPTON, Ga. -- On a day when one pothole after another lurked under hoods, Jimmie Johnson waited until the end of Sunday's Bass Pro Shops MBNA 500 to hit his.

Riding fifth late at Atlanta Motor Speedway, Johnson roared off with the leaders on a lap 307 restart. Only 18 laps remained in the 325-lap event, and Johnson, who'd run in the top five most of the afternoon, expected to be a factor.

	Jimmie Johnson

But somewhere along the backstretch, Johnson's Chevrolet suddenly fell off the pace. Cars swarmed past him on the inside and outside. He dropped to 10th in a millisecond, then onto the apron.

"This doesn't happen to us very often," said Johnson, who started 11th and led once for two laps.

Crew chief Chad Knaus pressed for radio details, asking Johnson if he was sure it was the engine. Johnson replied affirmatively. Five minutes after his crew raised the hood on pit road, they shut it and began the long push toward the garage.

"I went up through the gears and was in fourth coming off [Turn] 2," Johnson said. "I felt a really bad vibration, and that was it."

The engine failure was particularly aggravating because a top-tier finish might have propelled Johnson into the points lead. He started the day in third place, three points behind second-place Matt Kenseth and 11 points behind last week's leader, Michael Waltrip, who finished 27th. Johnson and Kenseth, who finished fourth, could have duked it out for the points lead -- but only if Johnson had stayed in the game.

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Instead, he exited on lap 308, finishing 32nd. The hard luck also dropped him to fourth in the standings, behind the new leader Kenseth, defending Winston Cup champion Tony Stewart and Waltrip.

"We're cranking these things really hard -- a lot of RPM," Jeff Gordon said of engines. "On those restarts, we were almost wide open there for one or two laps. You have no idea how much stress -- you can just hear the engine -- the RPMs it's turning, the stress that's being put on it."

Johnson wasn't the only driver bitten by mechanical gremlins. He was one of nine drivers sidelined by motor problems. Roush Racing took the biggest hit, losing the engines of Jeff Burton, Mark Martin and Kurt Busch. The Wood Brothers' Ricky Rudd, who also runs Roush engines, lost his late in the race. Other motor casualties belonged to Jamie McMurray, Bill Elliott, Ken Schrader and Larry Foyt.

But the biggest headaches belonged to the Roush camp. Even Kenseth had problems, but they weren't engine related. A balky power-steering system finally expired late in the day, and rookie teammate Greg Biffle, who finished 16th, ran his final 150 laps with his oil-pressure gauge blinking red.

Busch said the source of the engine problems remains a mystery. Roush teams also experienced intermittent reliability issues last season.

"We've always had a problem under the hood," Busch said. "We try and try and try. We gain horsepower, we're just not competing under the hood like the other teams."

Gordon, who finished second and is Johnson's teammate and team owner, said he got nervous once when his tachometer surged to 9,400 revolutions per minute. He wasn't sure why, whether it was working the gears back to race speed, but he admitted the reading unnerved him.

"It wasn't surprising me that guys were blowing," Gordon said. "I was just hoping that mine wouldn't."

According to Michael "Fatback" McSwain, winner Bobby Labonte's crew chief, any tachometer reading above 9,200 is cause for alarm.

"You get up around 9,400, 9,500, that's the danger zone," McSwain said.