LOUDON, N.H. — NASCAR, in an attempt to prevent teams from cheating and limit postrace talk to what happens on the race track, issued a stern warning to its drivers and crew chiefs at their prerace meeting Sunday at New Hampshire Motor Speedway.

The warning followed a frustrating week for the sport in which the Chicagoland Speedway race-winning car of Martin Truex Jr. and the 12th-place car of Jimmie Johnson failed postrace rear alignment measurements by the smallest amount in NASCAR’s three-tiered punishment system.

Because the typical 10-point penalty might not have impacted Truex — whose win counts toward advancing to the quarterfinal round of the Chase but could have severely impacted Johnson’s ability to advance — NASCAR decided Wednesday to wipe away the two lower tiers of its punishment system retroactive to Chicagoland and did not penalize Truex nor Johnson.

At the prerace drivers meeting Sunday, NASCAR Executive Vice President Steve O’Donnell told the drivers and crew chiefs:

“I want to make clear to everybody here that in NASCAR’s judgment, any measures that are taken to circumvent what happens for postrace inspection, we are going to react. We know that’s subjective. But ask all of you not to put it in our hands because we will react if we have to. I think everybody knows what that means. We want to concentrate on the race. … We couldn’t be more clear. I hope everybody agrees with that.”

A NASCAR spokesman said afterward that certainly could include a driver weaving the car after the race on the cool-down lap. Drivers have been weaving the car to allow parts and pieces — designed to move when at speed and under loads — to settle to go over the tech platform.

NASCAR could react with points penalties, fines, suspensions or the elimination of practice time in upcoming races.