This lesson is so different from the others that it's difficult to understand at first what is expected from you.
When you know this (see ^^^), the lesson becomes easy.
You can bring the pedal to the metal for a few seconds to increase your speed when you exit the big turns, then release the gas pedal until the gauge has dropped around 10.0. Then you can put some gas back to keep your speed.
Try to have the gauge at 9.9 when you cross the finish line, you'll pass the lesson.