They both happen at the same time it's a running engine always makes both so it's always making power, you have to give an engine a job to measure tq in a dyno but your akso measuring rpm, power.
Look at it this way take an engine less car with a one foot bar fixed to the front of the 4 gear and hang a 500 lb weight off it now you got 500 lbs-ft going to the driveline, it ain't gonna do much even if it moves the car an inch by the weight moving towards the ground it's using up it's potential energy, power.
