Stalling 90

[Robert Blumel]

Hey all,
After a brief hiatus, I'm back.  

I have a 1990 Audi 90 that I bought in California and drove back to MD.  After buying a 99 A4, I'm giving the 90 to my dad for a daily driver.

Problem is, after letting it sit for a while, something seems to have gone wrong and I'm going broke trying to fix it.

Here's the list:

a) stalls out randomly.  It'll stall right after you start it, pull away from the driveway, and stop at the stop sign.  It stalls when you turn right.  Then it won't do it again.  Then it will.  It;s really strange and it never did this before.

I had Tri-tec in Annapolis try to fix it b/c I'm just fed up, and they charged me $280 to replace the hose that goes from the ISV to something under the manifold.  it  didn't help.

They wanted $650 to do a tune up and replace the plugs, wires, cap and rotor and reset the fuel air mixture, which I of course said no to.  Replaced all those for $150 in an hour.  runs better, but still stalls.

I have it at tri-tec to have the cat and O2 sensor replaced.  You don't even want to know what they wanted for that.  I was thinking the O2 sensor might be bad since the cat is.

Any thoughts?  Maybe the Brake Bomb?

b)  The ac clutch won't kick in.  I was having trouble with the center vents before, but I replaced the relay and they're on now, but I still can't get the clutch to engage.  It's new, and I tested the compressor before I put it on to see if the clutch would engage and it did.  Any thoughts?

c) my antilock light is on, meaning the antilock is off.  I have no idea what's going on here.

It;s basically a good car, reliable transportation and all.  It looks good, too.  I just want to get it moving so my dad can get around.

I need the collective wisdom of the list.

TIA

Rob Blumel
99 A4
90 90
98 Saab 900 SE 2.0 Turbo (wife's)
80 Merecedes 300D
82 Toyota Land Crusier FJ60
87 Samurai