Humming while accelerating, not idling??

[Adam Berger]

I've been reading various posts regarding humming caused by the IAC but I'm not sure if the noise I get is from the same thing. I don't have a noise when idling, infact, the motor runs so smooth, it's almost like it's not running. The noise I get is normally when I leave my housing estate and enter the highway and accelerate. Not heavily but enough. During this acceleration I hear a quiet humming noise which sounds like it's coming from the engine bay. If I back off the pedal completely, and then accelerate again, it goes away and never comes back until next time I leave home. It also goes away on its own once I reach almost highway speed. It seems it only happens when the car hasn't warmed up yet. Anyone got any ideas?

 

[jimbo74]

maybe a vacuum problem or a problem with the fast idle when cold mechanism

 

[Adam Berger]

I should correct myself where I said humming. I think it's more of an induction noise, like sucking with a bit of wetness added to it. Do you know what I mean?