CONCORD, N.C. -- The primary cars of Scott Riggs and Johnny Sauter of Haas CNC Racing were impounded by NASCAR when it was discovered the rear wing mounts were illegal prior to Saturday's Sprint Cup practice.
Both teams will be allowed to use backup cars and start in the back of the field in Sunday's Coca-Cola 600.
Both teams also face further punishment by NASCAR. Dale Earnhardt Jr. was docked 100 championship points and crew chief Tony Eury Jr. fined $100,000 and suspended for six races last season for toying with the rear wing.
Riggs had qualified 13th and Sauter last.
NASCAR spokesman Kerry Tharp said the violation was discovered after it was brought to the governing body's attention there might be a problem with the location of the upper wing mounting points.
Inspections are not a normal part of the pre-practice routine on Saturday.
"The garage I would say is a fairly self-policing area,'' Tharp said. "We follow up on information we get."
Matt Borland, the competition director at Haas, said he was surprised to learn the cars were illegal. He and team officials were meeting before further commenting on the situation.
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.