High pitched whistle noise coming from under hood!

**Blue99ls1** · 10-01-2009, 08:30 AM

So the other day i was at a fast food dive thru and heard this high pitched whistle! Car runs fine when im on the throttle the noise stops but as soon as i let off the throttle it starts again. Now when the car is in neutral and i rev it up the car hangs out at the rpm that i stop revi g out and slowley cmes back down to normal! I was thinking a vaccum leakor something i cant pinpoint the noise! Anybody have any suggestions! Its a 99 z28 ls1 auto if that matters.

**tep98ws6** · 10-01-2009, 08:38 AM

http://www.ls1.com/forums/showthread.php?t=122727

similar?

**Blue99ls1** · 10-01-2009, 09:08 AM

Dosent seem to be with the description they gave. Mine is all the time not just after it warms up amd would a belt or tensioner affect the idle part i was describing. The car was running fine till the noise started then the idle thing started.

**Blue99ls1** · 10-01-2009, 09:11 AM

And mine is not really a chirping sound ive had that before and it was the belts. Mi es is like blowing a high pitched whistle all the time then stop when i push the gas and as lng as im on the throttle it dosent do it but as soon as i let off it starts at any speed

**Blue99ls1** · 10-01-2009, 01:32 PM

I found out what it was. It is the little piece of hose that goes from the intake manifold on the pass side of the car to what im guessing is the PVC valve. The hose had a hole in it and was melted. I just need to know if anyone knows what the hose is called so i can order a new one.

Heres are links to the pics not the best in the world but its from my iphone

http://yfrog.com/0pimg0090azj

http://yfrog.com/3oimg0091uij

**SteveCZ28** · 10-01-2009, 04:42 PM

just take a chunk of i believe 3/8 inside diameter hose cut to length and slap it on ther....like a .22 cent fix

**ghostriderb** · 10-08-2009, 05:46 PM

Just started having this exact same problem. So what is the verdict?

**Blue99ls1** · 10-08-2009, 05:53 PM

I did like what was said the post above and replaced it with a piece of 3/4 hose and i havent had any problems so far.

**Patrick** · 10-08-2009, 06:02 PM

Geez... I wish this was posted a couple of weeks ago. I helped a buddy install an single Turbo LS1 in a 2nd gen RX-7. We had the exact same problem. We were convinced that it was metal on metal. So much so that we actually pulled the tranny thinking it was some sort of interference with the flywheel!! I would have bet $100 bucks that it was not a vacuum leak.

I'm glad you got it resolved quickly and without much effort.