Particular revs problem

[kavadarci]

Hi,
My car starts fine and idles fine.
Upshifting and downshifting is no problem.
The only time I have problem is when I’m at a lift for example and rev the engine a little bit., 3k for example, on the way down the engine stalls.
Starts right up no problem.

What might be causing the engine to stall on the revs down?

Thank you.

[DRACO A5OG]

Sounds like a vacuum leak