After leading twice for just one lap, pole-sitter AJ Allmendinger took his No. 47 Chevrolet to the garage on Lap 64 with mechanical issues.
Allmendinger, who was a favorite to win the Toyota/ Save Mart 350 at Sonoma Raceway, had pitted a few laps earlier and had the hood raised on his car.
In the garage, the No. 47 crew changed the fuel cell in the car to prepare to send Allmendinger back on the track. The No. 47 was 12 laps down when it returned.