Whine and High Idle

[rumbold11]

I started my truck the other night, and it was making a whining noise that varies in pitch and cant be heard from the outside, but that also could be because my exhaust is too loud. It goes away when i give it gas. Also now it idles at about 1100-1200 rpm's most of the time. It'll go back down to normal if I'm lucky. Any input on what is wrong is greatly appreciated!

 

[vaderj]

IAC? dont know about the the older ones, but apparently its a pretty common thing with 98-whenever; Mine had a similar issue

 

[erikm]

my 95 had the same similar issue, except it was more of a howling noise. my dad( ford mechanic for 40+years) said to smack the IAC with a screw driver(handle end) when the noise was occurring and see if the pitch of the noise changes, it did on mine so i replaced the IAC and haven't had the problem since....