As a new Prius owner, I am not sure if this is a normal thing or something I should be concerned of. I drive mostly in Eco mode and I noticed if I depress the gas pedal hard in order to quickly accelerate, the engine starts making a constant noise/sound as soon as it hits the PWR range in the hybrid system indicator. As the acceleration falls out of PWR range, the sound goes away and engine sounds "normal". FYI, I am not sure if the same sound occurs in Normal or Power driving modes also as I didn't drive much in those modes yet. I keep hearing Prius is a very quiet car. So I am not sure if something is wrong with it. If it is, what should I do?
As with any internal combustion engine, it makes sound. The harder you press on the gas pedal, the more sound it makes. In fact, the same device on a motorcycle is often called "the loud stick."
Enjoy the awesome car. I think it's one of the best cars made, especially for its intended purpose of efficient, economical transportation.
