Ok I got to the house and right before I turned the rig off I glanced at the gauges and it was sitting at 450rpms. It wasn't rough and if I hadn't looked at it I never would have known. So I goose it a little and the idle returns to 450. Decide to drive it around the block and as I pull out I hear a moaning sound, like a very very faint owl, sort of a "whooooooooooooooo". Once I get out of the driveway the noise is gone, only does it in 1st and reverse, only when I'm moving very slowly and only when I'm leaving a dead stop. I made the block, came back to the house and the idle was back to normal. I took a look under the hood at the vac lines thinking it was a little leak but couldnt' find anything.


Thoughts anyone?

 

Fan clutch grabbing?

 

your idle air valve started to work properly and now you can adjust the idle speed the way it's supposed to be?