I have a1985 E-150 ford van with 5.8 Litre engine.It started acting funny and didnt want to idle write.The engine light went off and is currently staying off but now it is stuck on high idle.Im not sure how to check the intake air control valve but I disconected it and it returned to low idle but wouldnt run this way due to it wanting to die at stops.Does this sound like the iac is bad or could it be something else?Any suggestions would be welcomed and thanks in advance.