Help! Difficulty Starting my '86 4kQ

[Chad Frederick <fredie@u.washington.edu>]

I am in need of a lot of help.  I am a poor Univ. of Washington student and
just purchased my first Audi several weeks ago.  It is a '86 4kQ.  My
friend and I were installing a new stereo in it several days ago and when
we were finished I started up the car and it began to idle extremely rough
and with a very low idle.  I then proceeded to drive the Audi and it drove
great as usual but my trip computer was not registering the MPG at all,
just showing lines.  Everything else worked on the computer except the
average MPG read 200. I looked in the fuse box and the computer fuse had
blown so I replaced it, but had no luck in it working correctly (I thought
maybe I had to reset it manually some how.) The next day I went out to
start it and it would turn over and even fire but will not start. It just
kept sputtering and dieing.  A day ago my Audi ran great. It acts as if it
wants to start but it just won't.  I have called many local resources and I
heard it is anything from me needing a new fuel pump (I can hear it winding
when I turn the ignition so I think it is alright), to I need a new fuse
box(my friend had a very similar proplem with his '85 coupe and the shop
replaced his fuse/relay box, that fixed the problem.)  I cannot afford to
take it to a shop so if anyone knows what else I can trouble shoot/replace
to fix it, or has had a similar problem, it would be most appreciated for
your advice.