would anybody know y there is a loud hissing noise coming from the intake? its making my car run at 1000rmp. could if be a vacume problem?

 

YOu could have a leak, but it is also common for a hissing to be present with an intake primarliy at low rpms.

 

but it wasnt like that b4? i had the car 4 a year or so and now the rpm are bouncing up and down when i stop between about 900rpm and 1200rmp? and i know the hissing ur talking about but just think like 3 or 4 times louder? so it could prossibly b a vacume leak? some one told me change the O2 senors but i dont think that could b the problem

 

Sounds like you have a leak or the IAC is going.

The o2 sensor has nothing to do with the car idling.

Pull the IAC off and give it a cleaning and check all the connections.

 

Where can i find the IAC?

 

IAC:




[IMG]local://upfiles/14091/557D4AE2BBE641ADA1BE09ABBD99EBF5.jpg[/IMG]

 

just cleaned it and no difference

 

96 GT and you have a multitude of issues judging by your past 12 posts.

Did you replace the plugs and wires yet?

Are you running any accessories while it is idling high?

Does it only do this when it is cold?

Is the car an auto or stick?

Does it do it when the clutch depressed/(auto) in gear

 

check the main vacuum line on the back of the plenum, when I did my plenum swap I forgot to hook it back up and it wouldnt idle right. same symptoms or at least it sound like it. made the same hissing sound too

good luck

 

most of the time cleaning the IAC won't work. you need to replace it, all the parts shops have them. I think that there like 75