are spark plug wires interchangeable with other years and models of the car. on 1991 Audi 90

I need one wire for my Audi 90 and I can't buy a set. It the core wire.

Asked by for the 1991 Audi 90
2 answers
Your local parts store should have a breakdown of what is required for each wire in a set or take old one in and they can match.
Look at www.rockauto.com ,they usually have good images of parts, see if the part number crosses over to any other car.