'87 5KCSTQ Idle Stab Valve or Relay?

[Rob Silcher <rsilcher@mc4adm.UWaterloo.ca>]

Still having trouble with my idle.  The valve has been cleaned well - the 
car idles well on startup. However, when driving around town the revs 
seem to hang up in the 2000+ range at idle before coming down slowly.  If 
I disconnect the connection to the valve the revs come down immediately.

Michael Spiers mentioned it could be the idle relay.  So my question is how
can I determine if the valve or relay is the culprit without spending alot of
money on each part?  Right now I leave it disconnected - works great when the
engine is warm - at startup, though, have to keep your foot on the gas. 

On another note, I also can't determine what is causing my hard starting 
when the engine is hot and sits for 1/2 hour. Went out for dinner last 
night, got back to the car after about 45 minutes and it took about 2 
minutes to get the car started. After it starts it kind of runs rough for 
a few minutes. If the car is only sitting for 15 minutes it starts no 
problem.  Starts great when its cold.

-Rob Silcher