oil consumption

[gad@advanced-robotics-research-centre.salford.ac.uk (Graham Dalton)]

My 1986 Audi 90 (2ltr 5cyl, 82000mls) is consuming oil at the rate of 1 litre/1000 miles. Looking at the manual, this is within Audis own limits. However, I think this is far too high for a car like this especially since my friends car with an identical spec. consumes no oil.

I'm using Mobil 1 synthetic and its consumption habits are making this a costly problem. I'm begining to wonder whether its even worth changing the oil at all since in 5000 miles I've completely replenished the contents of the sump!.

Does anyone have any pointers as to what the root of the problem may be?

I've also got a steering 'shimmy' at around 85mph and have been told the steering toe-in is slightly out. What are the likely causes of this bearing in mind that the front wheels have already been balanced.

Thanks in advance 

Graham Dalton