[V8] Idle Stabilisation Valve

[toml99 at todomundo.com]

Hey, gonna put all the squaking of my IC in the back of my mind right now to let Ed figure it out.....5-speed still idles high.  Basically idled high since I got it.  Recently after getting it running, realized the #5 injector was leaking profusely.  Decided to just pull that one and replace with spare and make sure it was clean.    Found a UTube vid of a guy with a 5cc syringe that took the nozzle of a carb spray can in the needle end, and the injector fit with a slighly smaller oring in the plunger end.  Back flushed injector with a simple push button switch hooked up to battery/pressure from spray can.  Threw injector in and all was well, or so I thought.   
Still idles high(but smooth which it didn't before injector).  ISV was previously cleaned and works flawlessly as do the other 2 spares.  Service training manual states that ECU sends a "duty cycle" to maintain idle.  I checked and 5-speed opens wide open/checked same good ISV on Lago, and it only opens maybe 1/2 way(where it most likely should)......Swapped ECU's and all was same.  Anyone who know's ECU's may be able to answer how it figures out the "duty cycle" for idle.  Could be an air leak, but a full can of carb spray detected no leaks anywhere....Both Heads were replaced at about 150K and maybe there's a leak in the throttle body, but would assume I"d find it with spray......Car runs like the beast it's supposed to be, just idles around 950   Any Ideas?  Tom