83 ur-q frequency valve question

[Jeff & Staci Hemmerlin <hemmsta@sc.llu.edu>]

I have an 83 ur-q that has a rough idle.  

Ok,  I know they all idle a little rough.  My car stumbles while it is
idling.  This stumbling corresponds with the frequency valve skipping a
beat.  Normally the frequency valve is buzzing at idle.  In my car every
5-10 seconds it stops for a fraction of a second.  The engine then stumbles
at this same time.  

Here in southern California we are beginning to see some warmer weather.
This stumbling problem changes when the car is warmed up on a warm day 80
degrees+.  The frequency valve will be skipping along as described above.
Then it will then stop all together. The engine will then loose rpm's and
stumble until it dies.  Usually in about 15 sec.  When the frequency valve
is buzzing the duty cycle is bouncing from 47-52%.  When the frequency
valve quits the duty cycle rapidly climbs to 82.3%.

This is related to a post that I placed last month.  Heat and my ur-q don't
mix. 

TIA

Jeff Hemmerlin 
95 S6
82 ur-q (collectable and for sale)