If you take an engine out of a car and try to spin it by turning the crank shaft, it will be hard to turn because the cylinders need to compress air (it’s required before adding fuel and spark to explode that compressed air so it expands).
When that engine is in the car, and you don’t add fuel and spark, then the cars wheels have to turn the engine and compress that air, thousands of times per minute. That force that the wheels have to send to the engine to spin that engine slows you down.
I’m thinking you think the engine itself has a brake on it… No.