Stalls when I press the clutch in with the A/C on
 

Why would it do it with A/C on and not do it with the A/C off.

AC compressor is a significant load and the 79 doesn't have adaptive idle control. Thus, the compressor load is enough to stall the engine. My '75 ('79 engine) drops about 50rpm when I turn the AC on... its tough to tell because the tach goes non-linear at 1k rpm.

Couple of questions for you-

With the AC off, do the RPMs fall past idle, bounce/hunt, and then stabilize?
With the AC on, do the RPMs fall and then stall?
What RPM are you releasing the clutch at (when this happens)? (above 2k, 3k, etc)
What is your idle with the AC off? (should be 850-950, right below the 1K hash mark)
Does your idle hunt (bounce up and down)?
Are there any other symptoms - low power at idle?

Perhaps you should check the high side pressure of your AC compressor, If it is developing enough resistance to bog your engine down that would suggest either a restriction in your condenser or your high side lines. Even on the cars with-out idle stabilization this abnormal.

My car is going back to Don Jackson in Glendale, AZ tomorrow. He changed out my refrigerant from 134A to R12 on Thursday and it did nothing but cost me $290.00.
I need to get to the bottom of this or I wont be able to sleep, the AC problem is driving me crazy.

hey guys! sorry to butt in.... my 79 with a 3.2 transplant does the same thing... dies out with the AC on. It doesn't do it all the time but enough time that it discourages me to use my AC. here are some symptoms that i am getting..

with AC off
Idle hunts at cold start, doesn't kill the engine and only cycles about 3 to 4 times before going to normal.

idel hunts very little through out the day, only by a couple hundred RMP. idle stays right below 1K.

With AC on:
hot or cold engine dies at stop or when clutch is pushed in. not all the time, mostly seen when pressing the clutch in at higher RMP, say above 2500?

engine bogs at start on both 1st and sometimes at 2nd gear

Any update on this?

I still haven't figured out what's wrong with my car. I did however chech the AC pressure and both high an low is within specs. I did notice some vacuum leak around the intake manifold where it meets the head and some on the rubber hose connecting the two intake manifolds. I haven't had a chance to fix this yet so I'm not sure if this is the cause of my issue with the AC/idle

toysRus,
Fix your vacuum leaks and follow the advice in this thread.
http://forums.pelicanparts.com/porsche-911-technical-forum/566846-1985-3-2-no-idle-rich-advice.html