Joe Gibbs Racing will not file an appeal with NASCAR over its decision to disqualify Denny Hamlin and Kyle Busch from Sunday's race at Pocono.

The pair finished the event in first and second place, but were stripped of their positions after their Toyota Camrys were found to be in violation of NASCAR rules during a post-race inspection.

NASCAR's Senior VP of Competition Scott Miller has now revealed that extra strips of material were found under the decorative vinyl sponsor wraps of the vehicles that put them out of acceptable specifications.

"It was on the lower fascia and it was extra layers of vinyl that in effect deviated the part from the approved CAD files," Miller told SiriusXM NASCAR radio on Monday.

Denny hamlin car front

Hamlin was disqualified because of a strip of tape installed under his car's sponsor wrap at the lower corner of the front fascia ahead of the wheels.  (Rich Graessle/Icon Sportswire via Getty Images)

"It’s standard procedure for post-race inspection to peel vinyl off parts of the car that we feel are critical. We had no inclination prior that there was anything there and were very surprised at what we found."

DENNY HAMLIN WAS THE FIRST NASCAR CUP SERIES WINNER DISQUALIFIED SINCE 1960

Photos were not released, but Wally Brown, Joe Gibbs Racing director of racing, further explained the situation in a statement posted by the team.

Kyle Busch car front

Kyle Busch's Toyota Camry is physically identical to Hamlin's. (Rich Graessle/Icon Sportswire via Getty Images)

"In our review of the post-race infractions on the 11 and 18 cars at Pocono it was discovered that a single piece of clear tape was positioned over each of the lower corners of the front fascia ahead of the left-front and right-front wheel openings on both those cars," Brown said.

Hamlin and Busch

Hamlin and Busch finished the Pocono Cup Series race in first and second before being disqualified. (Rich Graessle/Icon Sportswire via Getty Images)

"The added pieces were 2 inches wide and 5.5 inches long with a thickness of 0.012 inches and installed under the wrap. This change in our build process was not properly vetted within our organization and we recognize it is against NASCAR's rules. We apologize to everyone for this mistake, and we have made changes to our procedures to ensure that it does not happen again."

The strips were about the size of a smartphone in surface area and half the thickness of a typical driver's license.

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Toyota and it's TRD racing arm said they were disappointed, but "applaud NASCAR's hyper-vigilance when it comes to policing the rules on this new race car."

Neither NASCAR nor Joe Gibbs Racing have detailed the potential effect the modification could have had on the speed of the vehicles.

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Further evaluations will be completed at NASCAR's R&D facility in North Carolina, according to Fox Sports reporter, Bob Pockrass.

Joe Gibbs Racings other two cars, driven by Martin Truex Jr. and Christopher Bell, were not required to be inspected under series rules.