Help!! my car doesn't run right

[NineK at aol.com]

Hi all,

I do all of the mechanical work on a Triumph Spitfire that I own. But my 
wife's car is a 1988 Audi 90 with a 4 cylinder and automatic and I don't know 
anything about it.

The first clue. When I start the car the idle is really rough - it bounces 
between 500 and 2000 rpm's - but it will idle.

The next clue. When I put it into gear it is even rougher.

And the final clue is that when driving between 30 and 60 mph and I let my 
foot off of the gas the rpm's will not drop back down.  The engine will rev 
on its own.

Can anyone help me solve this puzzle?

Bob Berger
88 Audi 90
78 Triumph Spitfire