The fourth caution - the two most recent for NASCAR competition yellows - is out at lap 50 of the Quicken Loans 400 at the Michigan International Speedway. Marcos Ambrose held the lead at the caution flag after a thrilling three-wide pass of Matt Kenseth and the lapped car of Ken Schrader. Kenseth held second, ahead of Mark Martin, Greg Biffle, and Tony Stewart. Joey Logano, Clint Bowyer, Kyle Busch, and the Penske Dodges of A.J. Allmendinger and Brad Keselowski completed the top-10.
The first yellow of the race flew on the third lap when Kurt Busch got loose and spun off the second corner. Busch sustained damage to the left front of his Chevrolet in his first race since being suspended by NASCAR for last weekend's event at Pocono.
The second caution came when rookie Josh Wise's engine blew and oiled down the race track. It was the second engine failure of the race, as Trevor Bayne's Ford - which started seventh - broke a valve spring just after the restart for Busch's incident.