Remove the carpet in the trunk and there should be an access door on the gastank (the fuel pump is inside the tank).

Doesn't sound like fun, but it is do-able. Here are some tips:
http://www.audifans.com/pipermail/v8/2004-January/001026.html

Regards,

- Jeremy

1990 V8Q Zyclam Portland, Oregon (USA) http://www.MyV8Q.com/ Fun, Fun, Fun auf der Autobahn