Ryan Hunter-Reay drops out of Grand Prix on 42nd lap

Ryan Hunter-Reay, who won the IndyCar Series race in last year's Grand Prix of Baltimore, had a tough time defending his championship Sunday.

After starting eighth, Hunter-Reay's DHL Chevrolet had "electronics issues" nearly from the start. His car stalled on the first lap and he dropped down to 22nd. After clawing his way back into the top 10, the same problem resurfaced and Hunter-Reay had to drop out of the race on the 42nd lap. He was 20th at the time.

Hunter-Reay said afterward that the initial was an anti-stall mechanism malfunction at the start, but wasn't sure what caused his car to stall later on.

"It's heartbreaking," he said