On cars with manual transmissions, when in low gear (typically 1 or 2), why does accelerating and then taking your foot off the gas make the car lurch forward with that uneven, jerking motion?

Question

Why wouldn’t the car just decelerate smoothly when you take your foot off the gas? And why does it often continue even if you step on the gas again?

In: Engineering

Answer 1

The engine has flexible mounts to absorb vibrations. You are flexing those mounts when you do this, and it gets lurchy. You can rip them if you keep doing that.