I've got a 97 Golf that has recently gone from getting 650-700kms a tank to about 450 or less. The exhaust has started making black soot around the back of the car even though i just replaced parts of it. The air filter was checked and didn't need to be replaced, wondering if anyone else has had this happen and what they did about it?

 

Welcome to the forum jillbizzit.

How long is my piece of string?

Trying to diagnose excessive fuel consumption in a forum is like finding a needle in a hay stack.

The first thing you need to do is find someone with VAG-COM\VCDS to do an Autoscan to see what error codes come up then you will know which areas to look at first.