hey guys..got meself a 96 falcon xh ute..el style one..4 litre..went through 3 different mechanics and auto sparkies..none could figure out the problem..it idles at 2500 revs all the time..last bloke changed map sensons tps throttle body throttle idle and a whole heap of stuff..but still idles very high..if you unplug one of the sensors it will idle low again but starts blowing out black smoke n runs really rough..any ideas?

The engine can only rev like that if it is getting air from some where. If the throttle plate is closed, idle speed control valve port closed, remove the air duct off the throttle plate and stick your finger inside over the hole and the idle will drop right down if it is stuck open. Air in that volume can only come from brake booster hose, or from the pcv valve, or hose on the cam cover or on the inlet manifold underneath where it connects.

hey thanks mate i did that and the idle dropped down immediately as per normal..whats actually happening though how do i fix tht problem