Noise Source? - High pitched vaccum/damper sound.

[inetquestion]

Specs: 1998, 4.0, SOHC

I notice this noise slightly all the time. There is a slight hiss, but I'm unable to determine the source. It becomes much more noticable when I change the position (accelerate or decelerate) of the gas pedal on a smooth section of hi-way. It also does the same thing when the cruise control is active. This was actually my first suspect, but it is able to maintain constant speed, so I've kinda rulled this out. The noise almost sounds like its coming from inside the car possibly on the passenger side underneath the dash, but this is mere speculation on my part. It sounds vaguely like a leaking damper that has to equalize itself once the state changes. Again, more speculation on my part.

Anyone have any clues what is causing this?

TIA,

Inet

[airjxn]

I've started noticing the same thing on my 2002 Explorer. Did you ever find out what that noise was?

Originally Posted by inetquestion

Specs: 1998, 4.0, SOHC

I notice this noise slightly all the time. There is a slight hiss, but I'm unable to determine the source. It becomes much more noticable when I change the position (accelerate or decelerate) of the gas pedal on a smooth section of hi-way. It also does the same thing when the cruise control is active. This was actually my first suspect, but it is able to maintain constant speed, so I've kinda rulled this out. The noise almost sounds like its coming from inside the car possibly on the passenger side underneath the dash, but this is mere speculation on my part. It sounds vaguely like a leaking damper that has to equalize itself once the state changes. Again, more speculation on my part.

Anyone have any clues what is causing this?

TIA,

Inet

[inetquestion]

unfortunately I still haven't found the source. If you have better luck than I, please let me know.

-Inet

Originally Posted by airjxn

I've started noticing the same thing on my 2002 Explorer. Did you ever find out what that noise was?

[trox]

I noticed a hi pitched sqeal (vacuum leak sound) coming from behind my dashon my 2002. I just noticed it when it got cold. It goes away after a short while so I can't chase it down. Mine comes and goes with throttle as well. If I change heater control positions , it doesn't make any difference.

[airjxn]

I talked to a friend of mine who is a mechanic, and he said it sounded like a vacuum leak, but if it was it should set off the "check engine" light. I'm taking it in to him on Tuesday next week. If I find anything out, I'll let you all know...

[XLT98]

Trox,

I get the same thing with my 2002 also. Only when it's real cold out. It will stop if I increase or decrease on the gas pedel. It will go away after a short time. Let us know what you find out.

Jim

Originally Posted by trox

I noticed a hi pitched sqeal (vacuum leak sound) coming from behind my dashon my 2002. I just noticed it when it got cold. It goes away after a short while so I can't chase it down. Mine comes and goes with throttle as well. If I change heater control positions , it doesn't make any difference.

[inetquestion]

just checking to see if you found out what's causing this...

[trox]

Nothing yet, like you said, it only happens in really cold temps. It's hasn't been really cold in Kansas since I first started hearing it. I'd say from what I remember that it goes away when the passenger compartment warms up so it must be inside behind the dash. It will have to be pretty bad before I tear the dash out of this thing.