Also use normal foil??

I bought a prefabricated house and noticed that the vapor barrier was not installed properly (noticed when I wanted to drill outlets). Now I want to cover a wall again with a foil and install new drywall sheets. My question is, is that sensible? Can I use a simple foil? It is not a specified foil that is specially made for vapor barriers, but just a normal plastic foil that does not let anything through. If more information is needed, I will provide it immediately.

In my prefabricated house, in front of the vapor barrier (on the inside) there is another chipboard and then the gypsum board. If you now basically wrap the existing chipboard and the gypsum board on both sides in a vapor barrier, I can easily imagine that it will start to rot in between. Actually, you would have to remove everything on the wall until you get to the vapor barrier, renew this airtight layer, and restore the wall structure.

A vapor barrier is usually a PE film equipped with an aluminum coating so that it is absolutely vapor-tight. This property only comes from the coating of the film. If you want to be sure that there is no creeping moisture penetration, I would advise against using the existing film.

P.S. The vapor barrier is by far not the expensive part of the matter. The material to seal the vapor barrier is what costs money.

Buchenhunter

... I heard that the vapor barrier was not installed properly ...

What does "not properly" mean?

... now I want to cover a wall again with a foil and install new plasterboard panels. My question is, is that sensible?

If this is to be understood as meaning that the "improper vapor barrier (?)" and the existing drywall layer on the room side are to remain in order to install an additional proper vapor barrier plus additional drywall cladding, then I would generally have serious concerns.

... if more info is needed, I will add it immediately

To answer effectively, the following information would be helpful:
1. Was a blower door test with leakage inspection performed?
2. Exact wall structure from inside to outside with specific details for each component layer: material designation, material thickness, thermal conductivity, My or Sd value, detailed information on the quality of the installation, age of the material, etc.?

The assistance of a specialist on site is strongly recommended, as anything else could lead to not insignificant dangers for the building fabric.