With 23 of 82 laps remaining, Derrike Cope slowed on the track and was coasting through the bus stop when it appeared something exploded under the hood of his No. 70 Chevrolet. He was not injured.
A NASCAR spokesman confirmed the sanctioning body was impounding the car and would examine it back at its research and development center in Concord, N.C.
Crew chiefs speculate
"In my 35 years of racing, I've never experienced anything like that," said Cope after being evaluated and released from the infield care center. "It blew up in my face."