My folks have an 89 topaz, four cylender with air.  First they tell me
that it was making a "howling" noise which turns out to have been the
power steering fluid- low.  Added fluid, that fixed the howling.  But the
car has been stalling, on right turns.  I drove it for twenty minutes
today and couldn't get the thing to stall.  A couple months ago they
complained that the engine was idling too slow, and tended to kill unless
they kept up on the peddle.  I adjusted the idle speed and that seems to
have fixed that.

The steering and idle issues may be irrelevant but I mention them
because:

a) The low fluid in the steering may have caused a drag on the belt hence
dragging the rpms down.

b) Cranking the idle up may not have been the best way to address the
initial idle problem.

I thought this engine had a diagnostic computer that could be accessed
somehow i.e. flashing a code with the check engine light.  Does anyone
know if it does have a computer, and how to get the codes out?

The check engine light has been on for quite some time, I suspect that
this is an O2 sensor but for some reason dad won't have that changed.  

He's had it in the shop many times, but no one seems to address the
engine light issue for some reason.  The car was not acting up originally
when the light was on so it could be a short in the light system, but...

Fuel pump has been replaced in the last two years
Fuel filter likewise.
Tune up last summer
Ignitiom module replaced last winter
Cooling fan motor, car is not overheating

I replaced all this stuff as it failed not because I was guessing at what
was causing the stalls.

Any idea's or info on the computer would be appreciated.

Paul.