The engine makes whistling sound only when it's warmed up, and only on partial throttle. If I give more or less gas, the noise disappears. Maybe some type of vacuum leak? Any ideas?

(97 SC4).

 

my sc4 does that too from 2nd to 3rd gear but i have a intake that makes that noise. I like that noise though it kinda sounds like a baby wastegate.

 

Mine is pretty loud, and I don't really enjoy it. Pretty annoying in fact. I don't like noise...

 

i think i know that noise that your talking about ...like a really loud whinning noise when you accelerate, my car used 2 do that only in the rain for some odd reason, but it eventually went away..its probably a vacuum leak or something.

 

It probably is but where lol. There are so many little hoses, I hope I can figure it out today.

 

This is a long shot but I had that problem on my old 92 ES, it turned out to be the bearings on the alternator. Never experienced anything like it before or since. But it was making a loud whistling, and it was throughout the rpm range.

 

I love that sound too! Do you know if the SC300 makes that cool sound with an intake like the SC400 does?

Sorry to get off-topic, but I've always wondered about that.

 

idk i guess you can make it do that, il pm you a pic of the inside of my intake...its all you need to make that sound...

and for the loud whistling sound throughout the rpm range..i do remember changing out the alternator out so that could be the solution.

 

It is not throughout the rpm range but only happens around 2k rpm, and only on partial throttle. On full throttle it does not make any noise.

 

just did my valve cover gaskets.... got a strange whistle when it warms up. mine only happens when im off the gas. goes away when i give it a little gas.

 

Can anyone post up a good video of the actually noise?

 

Mine does this too! Makes it sound like it's supercharged