Pocono NASCAR Cup Series winner Denny Hamlin and runner-up Kyle Busch were disqualified after a post-race inspection of their cars turned up rules violations.
The Joe Gibbs Racing teammates were both stripped of their results.
"There was some issues discovered that affect aero in the vehicle," NASCAR Cup Series managing director Brad Moran said, referencing the front fascias of the cars.
"There really was no reason why there was some material that was somewhere it shouldn't have been. And that does basically come down to a DQ."
The decision handed the official victory to third-place Chase Elliott but can be appealed.
Both cars will be sent to NASCAR's R&D center in North Carolina for further evaluation.
Hamlin had temporarily become the first seven-time winner at Pocono Raceway and had also tied Tony Stewart on the all-time Cup Series wins list with 49 before the victory was rescinded.
Chase Elliott now has four wins on the season and sits in first place in the points standings.
The Associated Press contributed to this report