bizarre stalling behaviour 87 4kcsq

[Brendan Walsh]

Hey all, my new q is not so pristine as i thought. It's exhibiting a
bizarre stalling behaviour. Only happens when the car is hot, been
running for 1/2hr or more and returning to idle from cruising. I've
already gone over the vaccuum lines and can't see any obvious leaks,
one small white plastic line along the firewall was cracked. i patched
that with some duct tape for the moment, and the line for the vacuum
advance was sketchy so i replaced that entirely, Checked all the nuts
around the valve cover. I also soaked the ISV until the carb cleaner
came out clear and still no luck. If I blip the throttle as it comes
down it will keep idling, but it will pulse by about 200-300 rpms and
slowly even out. Sounds like my ISV is shot, or intermittent, but i
figured I'd pose the question to the experts. What's my next step
here? I was thinking to put hose clamps on all the vaccuum lines that
are supposed to be interferance fits(like in the egr system) .I 've
already gone around the engine bay with carb cleaner while the car was
running to try to find a leak, but no dice.I know from searching the
archives Alan had a similar problem in his 5K, but i didn't see a
resolution.

Thanks!
Brendan

-- 
"To err is human, to repent divine; to persist devilish." -Ben Franklin