Joe Gibbs Racing apologized for flunking a postrace inspection and declined to appeal the penalties that cost their drivers a win and second-place finish on Sunday.
NASCAR carried out its stiffest punishment against a race winner in more than 60 years when it stripped JGR's Denny Hamlin of his Pocono Raceway victory and teammate Kyle Busch of his runner-up finish.
NASCAR found issues in both of the Toyotas that affected the aerodynamics. Scott Miller, NASCAR's senior vice president of competition, said Monday on Sirius XM the exact issue was "extra layers of vinyl" found under the wrap of the car -- more commonly known as the paint scheme -- that essentially modified that area of the lower nose on each car.
"This change in our build process was not properly vetted within our organization and we recognize it is against NASCAR's rules," said Wally Brown, director of competition for Joe Gibbs Racing. "We apologize to everyone for this mistake, and we have made changes to our process to ensure that it doesn't happen again."
Hamlin was the first Cup winner to be disqualified since April 17, 1960, when Emanuel Zervakis' victory at Wilson Speedway in North Carolina was thrown out because of an oversized fuel tank. Hamlin was stripped of what would have been his third Cup Series win of the season and a track-record seventh at Pocono.
Chase Elliott finished in third place and was awarded the victory without the Hendrick Motorsports driver ever leading a lap in his No. 9 Chevrolet.
NASCAR introduced a new car this year that spent years in development and was designed to cut costs and essentially attempt to level the playing field. The 2022 version is pretty much a kit car; teams get all the same pieces from varying vendors and have detailed instructions regarding how to put it together.
And many of the pieces that fit under the car, items that used to cost hundreds of thousands annually to develop, are now spec parts that are essentially bought off store shelves. They're the same for everyone and not allowed to be manipulated.
Four years after NASCAR first threatened to tighten up inspection rules, it doubled down this season on going after potential rule benders.
NASCAR's three manufacturers -- Chevrolet, Ford and Toyota -- and their race teams never stop trying to find that extra edge that can give them more speed. They look for gray areas and wiggle room that give them an advantage yet keep them under the inspection radar.
"One of the early directives was that NASCAR was going to have to inspect these cars at a level that previously had never been done before," Miller said. "It's critical that we inspect at the level that we do and it's critical that we react when we see something that wasn't agreed on on the Next Gen concept."
Toyota Racing Development president David Wilson said the manufacturer stood by NASCAR's decision.
"As we've stated throughout the Next Gen process, we applaud NASCAR's hyper-vigilance when it comes to policing the rules on this new race car," Wilson said in a statement. "We have been in close communication with Joe Gibbs Racing and they have acknowledged that the tape added to the front facias of the #11 and the #18 was not permissible by NASCAR's rules."
NASCAR's inspection team usually tears down the first- and second-place cars at the track, and cars that finish third through fifth (such as Elliott's Chevrolet) are also inspected. All cars go through a prerace inspection, and multiple failures can result in the car losing its starting spot and getting sent to the back of the field.
NASCAR said the Toyota infractions were not caught in the prerace inspection because the wrap was not removed from the cars until after the race.
"This is not akin to a big engine or soaked tires or anything like this," Miller said. "This is more about the integrity of what was agreed on between NASCAR and the teams and protecting the integrity of the Next Gen inspection process."
The Associated Press contributed to this story.