Leading the second session for the GTS class on Friday at Sonoma was Mark Wilkins in the No. 38 Kinetic Motorsports Kia Optima.
Early on in the session, under partly cloudy skies and 79 degrees, Jack Baldwin of the No. 73 GTSport Racing Porsche Cayman S was at the top of the timesheet; he led the first GTS practice of the weekend earlier on Friday. Michael Cooper of the No. 10 Blackdog Speed Shop Chevrolet Camaro then took over at the top with a lap of 1:42.248.
After Cooper spent some time leading the second session of the day for the class, Wilkins put the No. 38 Kia Optima on top with a 1:41.874 - the time that would remain the quickest for the session.
The red flag came out about 20 minutes into the session as the No. 35 Phoenix American Motorsports Ford Mustang Boss 302 of Preston Calvert suffered a mechanical problem and sat motionless at Turn 5. With just two minutes remaining, the session returned to green after safety crew members removed the No. 35 car from its position stopped on track.
Behind Wilkins and Cooper was Ben Clucas, driver of the No. 36 Kinetic entry, rounding out the top-three with a best lap of 1:42.335.
Next up for the GTS category is qualifying for their Round 16 race, set for 12:55 pm ET on Saturday.
Stay tuned to @VAVELSportsCar on Twitter for continued Pirelli World Challenge coverage from Sonoma this weekend.
Aaron Durant is the editor of the VAVEL USA Racing section. Follow him on Twitter at @DoubleA291.