No power on hills - help desperately needed

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Hi all,
 
I have an automatic 1993 Audi Quattro 90S.  Last weekend I noticed a
loss of power on hills.  I haven't driven much until today and the
problem was much more pronounced.  Even slight hills gave me some
trouble and I crept up a steep one at 20mph with the pedal to the floor.
RPMs wouldn't top 3000.  I never had any trouble like this before last
weekend, but the car has only been driven 300 or so miles in the past 2
months.  Does anyone know what could be causing this?  I had thought
about a vacuum leak and I tried the "pull the dipstick" test and it kept
running fine so that likely isn't an issue.  I'm really at a loss here
and I'm afraid to even go for a drive because I'm afraid the car might
die on me.  I love my Audi but I'm scared to drive it.  Can anyone
please offer some suggestions?
 
Many thanks,
 
Tony