Check the idle switch, its underneath the throttle body. With the engine off make sure you hear a distinct click when the throttle is closed. I had to give mine a couple of taps with a hammer cos the bolts are a nightmare to get to!
Does it still haunt with the ISV disconnected? Also did you reset the ecu? Unplug blue sensor when the engine is up to temp, rev the engine 3 times over 3k then set up the CO and plug back in
