Stalling/Idle Problem Help?

[corylang@dccnet.com (Cory Langford)]

I figure I would bounce this problem off the list to get suggestions before
I started digging into a solution.

Plain CIS (not E) system.  Has been running fine for the last 7 months.
Last month is starts to drop very low in the rpm when you decelerate.
Yesterday when ever you take your foot off the gas and hit the clutch to
coast, the rpms drop and it stalls. 

Also, if you start it, it start fine, but will only idle for about 30
seconds before the idle slowly slips lower and then it stalls out.  I tries
bumping the idle speed up to 1500 just for "limp home mode" and all that
does is give it a little more time before stalling. It will sit at 1500 for
about 30-40 seconds and then slowly sink until it stalls.

If you let this happen at idle for a couple times, it get very hard to
start.  If you let it sit again for 30-40 seconds and then start, it fires
up right away but with the same problem.

Any ideas?

Off the top of my head I suspected either an air/vacuum leak somewhere
after the air plate, thus allowing the plate to drop closed while the
engine still gets air, but now no fuel.  

OR, fuel pump is going (I don't have a fuel pressure gauge to test it with.
 Something I am going to have to pick up eventually I guess) and the system
can't hold enough pressure to idle, but is able to get the gas at higher rpms.

Any comments are welcome :)

Cory