91 Roadmaster 5.0l extremely high idle.

[Austin_durbin]

I've got a 91 Roadmaster wagon with the 5.0l. Started the car earlier and it idle fine with a slight surge, let it run for a bit, shut it off for a couple minutes, and when I started it back it wanted to idle above 2000 Rpms. I've replaced the iacv, distributor, timed it correctly, replaced intake gaskets, ECT sensor, plugs, wires, tps sensor, spark control module, map sensor and this car is just being a nightmare. What is the probability of an ecm failure causing the iacv to open wide up? Anyone have a procedure for testing the ecm? Thanks in advance for any help. I really need it.

 

[MelsRegal]

Have you looked up the instructions for setting the IAC?

 

[Austin_durbin]

Yes I have. I believe that I set it correctly, and it was idling normally, I only shut it off for a couple minutes and when I started it back it's like the iac was wide open. I could hear a large amount of air entering through the port for the iac