90CS milage?

[Elliott Potter <epotter@abraxis.com>]

I've got a 1993 90CS (not quattro) that runs great except the milage
recently took a major turn for the worse.  I've not checked the exact
milage yet (no, I don't even have one of those fancy trip computer
things) but I've noticed that the gas needle moves down a fair amount
during short trips, ie. I took a half-hour trip home yesterday, about
half and half city/highway, no racing, no flooring, etc. (in fact I
rarely race, especially on public roads, so please no flaming for
that).  Any ideas?  The Audi garage recently had it for about 3 weeks
after they ran over something on the road while test driving it (long
story; it's in the archives from a month or so ago).  Any suggestions? 
The oil has about 4K miles on it, I don't know about the filter.

Thanks in advance.

Oh, by the way, as much as I would normally want the post to go to the
whole list, please at least copy any responses to e-mail; I get the
digest version of the list; I'm on #85, the list is on #138; I'm a
little behind:|
Thanks again

Elliott