Martin Truex Jr.'s second-place finish was marred by his No. 56 NAPA Toyota's failure to pass post-race inspection Saturday night following the NASCAR Sprint Cup race at Texas Motor Speedway.
The car did not pass the height requirement in the front end.
NASCAR public relations officials said the issue would be addressed at the start of the week.
Truex led 142 laps and posted his eighth top-10 finish in 16 starts at Texas. His second-place result elevated the driver from 25th to 16th in the points standings.
"It looks like there's something wrong with the left front shock that's holding it down," crew chief Chad Johnston said. "... We knew that either the rounds had backed out of it, or we had trouble with the left front shock, 'cause the rear was high because the front was so low. It sat over there, and typically, if it's choked down on bleed, it'll come up slowly, but it never came up. We had to beat the shock bolt out of it. It's definitely not something you'd want, but it is ...