JOLIET, Ill. (AP) ��� Jimmie Johnson had a strong car. He was in position for a fast start to the NASCAR Sprint Cup playoffs.
Then he committed another costly mistake.
Johnson led Sunday's playoff opener four times for a race-high 118 laps and was running second before he was handed a pass-through penalty for speeding on his way off pit road. The infraction on Lap 234 of 270 sent Johnson tumbling down the leaderboard, leading to a 12th-place finish.
Johnson's car also failed a post-race inspection, likely costing him some valuable points for the Chase standings.
Johnson, who turned 41 on Saturday, is going for his seventh series title, which would tie the record for NASCAR's top circuit held by Richard Petty and Dale Earnhardt. He was encouraged by the speed of his Hendrick Motorsports Chevrolet during the 400-mile race at Chicagoland Speedway, but the miscue on pit road left him shaking his head.
"This week we had it. This week we had it for sure," Johnson said. "Just the mistake there at the end on that last segment on pit road."
Johnson was coming off a rough night at Richmond, when he had a tire go down, hit the wall and finished 11th. He has just two wins this year for his smallest total since he also won twice during the 2011 season.
But Johnson, who has never won at Chicagoland and hasn't made it out of the second round in the two years of the Chase's elimination format, had the fastest car in Friday's practice at the 1.5-mile asphalt oval. He started eighth after qualifying was rained out and passed Brad Keselowski to grab the lead for the first time on Lap 53.
Johnson controlled most of the middle of the race before Chase Elliott took over the top spot. But Johnson appeared to be in good shape before the penalty on pit road, drawing a "no way!" from the driver on his radio when he was told of the punishment.
"I mean I was completely shocked that I was fast, because I'm way under, just being cautious," he said after the race. "Still got dinged leaving that last segment. I mean I couldn't believe it. Just mind-boggling."
Johnson was eighth in the playoff standings after Chicagoland, pending NASCAR's announcement of the exact penalty for failing the inspection. The field for the 10-race Chase is cut from 16 to 12 in two weeks.
"It's not as bad as I expected," Johnson said when asked about the Chase standings. "But just got to stop screwing up."
Jay Cohen can be reached at http://www.twitter.com/jcohenap