high pitched whistle sound in my 420a

[DravenC]

Hi! Recently my GS '98 std makes a high pitched whistle-like noise when you release the gas pedal after having been pressed, actually sounds like a kettle. Is strange because there is no CEL. The first time I heard it I thought it was a tranny related problem but there is no change if you engage or not the clutch and only comes when engine is hot, before everything is normal.

Here two videos, sorry for the bad quality because my crappy phone but you can hear that sound.

From engine bay
MOV00796.flv video by corvx96 - Photobucket

From inside
MOV00781.flv video by corvx96 - Photobucket

Can anyone help me? Any thoughts would be appreciated.

 

[SpawnedX]

You got vaacuum leak bro.

Immediately upon letting off the throttle, your engine is actually has a higher vaacuum pressure than normal, which is going to amplify this sound noticeably, because extra air is being sucked into the system from a tiny hole, which will make a whistling noise.

The higher pitch and louder the noise, the smaller the leak is in most cases.

You just need to inspect your system for the hole, check wires for cracking and pitting, etc. It's just one of those issues that takes time and investigation, a typical ball buster job.

 

[DravenC]

ahhh I see. Thanks for the info. Today, after driving to my home, that sound comes again, but I think it comes from the back of the intake manifold, tomorrow I'm going to check hoses and vacuum lines.

Thank you very much!