NASCAR has denied ThorSport Racing’s request to reinstate its two Gander Outdoors Truck Series teams that were eliminated at Las Vegas Motor Speedway because of a motor issue that Illmor Engineering claimed responsibility.

ThorSport Racing sent NASCAR a letter Sept. 27 seeking reinstatement into the playoffs for Grant Enfinger, the regular-season champion, and Johnny Sauter. Both failed to finish at Las Vegas because of engine issues and were eliminated from the playoffs.

Ilmor Engineering provides the NT1 engine that is run by nearly every team in the Truck series. After multiple engine failures during the Sept. 13 Las Vegas race, Ilmor and NASCAR investigated the matter. Ilmor Engineering cited the cause as “the combination of the high engine load condition combined with the extreme weather conditions in Las Vegas resulted in some engines suffering severe detonation.”

ThorSport Racing sent a one-page letter Sept. 27 to NASCAR with its request.

“We feel the right thing for us is we were never allowed to race at Vegas for the playoff positions,” David Pepper, general manager of ThorSport Racing, told NBC Sports on Sept. 27. “We’re not asking to reset Vegas. We’ll take our last-place finishes. We’re just asking to move the cutoff date to Phoenix, eliminate four of us instead of two (after Vegas) and two (after Phoenix.)

“Allow it to be settled on the race track and not by an outside source that has openly said, ‘Hey, we made a mistake.’ I don’t want to beat on them. They made a mistake, but we shouldn’t be the victims of the mistake.”

The six drivers remaining in the Truck playoff are: Reigning series champion Brett Moffitt, Austin Hill, Ross Chastain, Stewart Friesen, Matt Crafton and Tyler Ankrum.

The second round of the playoffs begin Oct. 12 at Talladega Superspeedway.