Once more into the void - flashlight?

[Fuzzzydog]

thanks for the quick replies and ideas....

Huw - I should have mentioned I did take a good look at the throttle
butterfly - they spring is very strong and any time I have manualy flipped
it open it always returned fully closed.  the throttle body is very clean

Adam - I will check again for vac leaks.  correct me if I am wrong, but at
high idle there would be boost in the intake and therefore I can't check for
vac leaks by allowing propane to flow over the engine, right?  so visual
inspection is the only option?

Bob - I'm almost 100% sure that the idle switch and ISV are ok, but you
never know - I may end up buying new ones just to be 100%....

what about that miss just off idle, after coasting?  can anyone come up with
something that would cause that symptom.  Would a vac leak do that?
also, just from different running at different temps, I get the feeling this
might be temp related - maybe the ecu is not getting a proper temp signal?

I did try disconnecting the cold start valve just in case it was tricked
into being on but that didn't do a think....