idle air control valve, Questions

[modelageek]

I have a miss/ hesitation that I am chasing. I disconnected the connection on my iacv (the truck was warmed up) the idle did not change. I drove the truck about 3 miles it ran a little worse but not horrible. I pulled it off cleaned it again. I then checked my vacuum at the intake manifild it stayed at 17. when i revved the engine it dropped way down and then went up to about 20 and would stay the if i held the throttle. I would like any feedback. I think the truck is suppose to stall or idle very bad when i disconnect the iacv. does this mean my iacv is bad or is there another issue casuing it. thx

 

[BogusSVO]

sounds like the IAc is bad, it should have died when disconnected... maybe the cuirb side idle scew has been adjusted when the iac went bad

 

[modelageek]

sounds like the IAc is bad, it should have died when disconnected... maybe the cuirb side idle scew has been adjusted when the iac went bad

Do I have a curb idle screw on a 99

 

[bduke23]

I have had IAC problems with another vehicle (Pontiac Fiero), where the IAC was stuck wide open. If you disconnect it completely and it isn't blocked, the engine should idle very high, or at least mine did. And with it not working, as you accelerate it does not change the amount of air it lets in, and as a result you will get dead spots and bucking. You could try testing the IAC motor to see if it works. If it does, then perhaps your computer is the culprit? That was the case for me

 

[cf3232]

How do yoiu test an IAC motor?

 

[bduke23]

Hook it up to some 12 volt leads, the little cone part should step out or in a bit and it'll make a sort of clunking noise... basically if you've tried touching all the prongs with power and nothing happens its shot