The men were cited for NASCAR for rules violations during a post-race inspection of cars driven by Joey Logano and Tony Stewart following the Carfax 250 at the Michigan International Speedway in Brooklyn.

"In our post-race inspection, inspectors discovered some shims that were placed on the gas-pedal stop," said Robin Pemberton, NASCAR's vice president of competition in a release. "They were magnets that were about a quarter-inch thick that prevented the accelerator from going 100 percent wide open."

Both Logano and Stewart were fined $50,000 while Gibbs was penalized 150 championship owner points for each car.

"We take full responsibility and accept the penalties NASCAR has levied against us today," Gibbs said in a statement, (but) we are disappointed that NASCAR chose to place our drivers on probation, as they had no knowledge or involvement of this incident."