What causes the engine of my Audi 80 to make a rattling noise when accelerating?

I've noticed that my Audi 80 makes a rattling noise when I accelerate, but it seems to go away when I am driving at a steady speed or when the car is in neutral. What could be causing this issue?

From the information provided, it sounds like the issue could be with your engine's timing belt. It is important to get this checked by a mechanic as soon as possible to avoid any potential damage to the engine.