Not True. When you are at 3000rpm and in gear with the throttle closed, you engine is pumping only air through it, thus engine braking, which is why if you are coasting with closed throttle, you are slowing down.
Your engine does not burn gas at any rpm with the throttle closed, with the exception of idle.
Unless (There always is an unless) you have a pesky EVO like I do, which if you are above a certain RPM, not sure where the cutoff is, and you close the throttle, it will burn a small amount of gas so that you don’t get bucked by letting off the gas suddenly. I know that if I am in say, 3rd gear, about 6,500rpm’s and you suddenly close the throttle, it will come down gently because the car is burning gas to keep it from reving down fast. At a certain RPM, it will shut the gas off, and you will see the car start to slow even more than before. I think the window is somewhere between about 4,000 and redline…