Sauter made the winning pass in his Toyota around Parker Kligerman, who took only two tires his last stop and couldn’t hold on to the lead.
Season points leader James Buescher, who started second in Chevrolet, finished 11th — the last truck on the lead lap. With two races left, his points lead over Ty Dillon was cut from 21 to 15.
Dillon finished fifth in his Chevrolet. He led only one lap, late in the race when he stayed out during the last cycle of green-flag stops to pick up a bonus point.
It was the sixth career victory for Sauter, who became the third driver to sweep both races at the 1 1/2-mile high-banked Texas track in the same season.
Sauter, who finished 2.2 seconds ahead of Kligerman, led twice for 28 laps and won the fastest race at NASCAR Truck Series history with an average speed of 154.734 mph. There were only two cautions, slowing the race down for only eight laps.
Nelson Piquet Jr., the polesitter who led twice for a race-high 65 laps, finished third and Kyle Busch was fourth.
Buescher started second beside his teammate, Piquet, and was still running in the front group when Matt Crafton made contact with him on the restart after the second caution about halfway through the 147-lap race.
After that Buescher started dropping back and was passed by Dillon a few laps later. Along with some body damage to the truck, Buescher was heard on the radio talking about a bad vibration in the vehicle.
Buescher, who is from Plano, has won on the dirt track, one-fifth mile track, quarter-mile front-stretch layout and the road course at Texas Motor Speedway. But he’s now 0 for 8 on the main track.