I remember seeing this when i was little, I would estimate ca. 1990, although from my memory I would estimate the movie in question to be more around 1970s.

I watched the movie on German TV, but am pretty certain it was an American production, possibly B-Movie.

I would think the movie was maybe set in Chicago or Detroit (only because of cars?), possibly, there might have been a death scene in a multi story car park.

The basic overall synopsis of the story in my memory is about a woman which after being killed by a group of men(?) comes back from the dead to haunt her killers. – She appears a seductive healthy woman approaching her victims but when she turns her back, her backside is that of a corpse/demon(?). (I believe in the death scene mentioned above her appearance is so shocking that a man jumps/falls from said multi story car park.)

The memory of this movie is still a haunting one after about 30 years.