Hissing noise on deceleration

[JDM_FL5]

I recently installed the prl intake tubes, drop in afe filter and a remark exhaust on my car and now when I’m driving I have a hissing type noise when my foot’s off the pedal and the car is decelerating under load. When I give it gas it goes away and when I push the clutch in while it’s decelerating it goes away. Is this just throttle noise or could it possibly be a bearing issue? I had a 99 si years ago with a intake on it and it made the same noise cause of the intake being able to suck in more air but it made the noise at all times so it brings concern that it may be something else. Any input would be great. Thanks.

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[MERAKIAUTOWORKS]

I have this issue as well, no clue what it is.

-Josh

 

[JDM_FL5]

I have this issue as well, no clue what it is.

-Josh

Have you taking it in to have it looked at? I feel like it’s throttle hissing cause of the plate closing mostly when I take my foot off the pedal but I’m not 100% sure. What mods do you have done to your engine?

 

[JDM_FL5]

Just to make sure- are you talking about a hissing or the infamous wastegate rattle? The rattle is perfectly normal, but if there’s a hissing, that’s likely not normal. Hard to tell without an audio clip.

Here’s a link to the normal wastegate rattle:

I don’t think it’s the watergate rattle. It sounds more like what I would consider a vacuum leak to sound like. I can’t get a video though cause it’s very faint and only happens when driving. I may just have to take it to the dealership and have a tech ride with me. Either that or put the factory intake back on and see if it goes away.

 

[Car00071]

I don’t think it’s the watergate rattle. It sounds more like what I would consider a vacuum leak to sound like. I can’t get a video though cause it’s very faint and only happens when driving. I may just have to take it to the dealership and have a tech ride with me. Either that or put the factory intake back on and see if it goes away.

If you take it to the dealer put the factory intake on otherwise they’ll probably tell you that’s the issue.

 

[MERAKIAUTOWORKS]

Mine is the waste gate rattle.

-Josh

 

[jcm]

i have a similar issue, brand new 2025 fl5 700 miles

decelerating, any gear, 2k-3k rpm very high pitch hissing/whistle when engine breaking lifting off gas entirely. also occurs during shift sometimes. only audible with windows down, very annoying.

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