Tech: 85' 8v Stalls at idle

[kkrup62 at hotmail.com (Karl Krupke)]

Hi all,
    My '85 8v just developed a glitch; stalling at idle. Restarts easily 
enough with a little throttle (warm or cold), just won't stay running on its 
own.
    I'm more familiar with the Mk 1 CIS system, this is my first Mk 2. I've 
looked (briefly) for a vacuum leak in all the usual places (all hoses on FR 
side of manifold, hoses to and from AAR on back of manifold, boots on the 
air box and at the throttle body), can't find anything wrong. I'll give it a 
more thorough exam over the weekend.
    Also, the idle speed has been non-constant since I bought the car a 
couple of months ago, I think it's the "idle speed boost valve" [Bentley 
page 5-28] cycling. Warmed-up, at idle, no load, idle cycles up and down, up 
and down. As of today I don't know if that's still happening 'cuz the bloody 
thing stalls out...
    Like I said I'm more attuned to early CIS, this system has some updates 
that are new to me. I'd appreciate any help along the lines of "oh yeah, 
such-and-such is a common problem on that year, check that". The car does 
have A/C, but I don't use it.
    Nothing to back it up with but my intuition points at the idle speed 
boost valve. Anybody got an idea on taking it out of the equation; ie. 
bypass it?
    I'm probably missing something stupid, but I haven't quite got my head 
back in Bosch-think yet.
    Thanks for the help.

Karl