Thread: Weird whistle/rattle when in low revs/idling

So in my 05 GP GT, I'll turn it on and listen to the normal chatter from the lifters, mild and goes away once the engine comes to temperature, and start driving.

Besides a whistle at WOT (which I think is due to a small intake leak), I noticed that sometimes while idling and almost always while at low revs, say 4th gear cruising at 40 mph in the city, there's a faint but still audible rattle, like at the pitch of a high-pitched whistle. Kind of intermittent but it's pretty much always there.

No codes are being thrown, and the car runs very smooth, I'm just curious as to what it could be. I'm saving up for a NA cam swap (GT cam from zzp) with new valve springs/lifters/gaskets all around so it'd be great if I could remedy this while I have the engine torn down in a few months.

Thanks for any input!

Good point! I never thought about the possibility of both issues being linked. In that case it must be from the engine, not the intake, you can't really hear it outside of the car.

Where do you think a vacuum leak would most likely occur? I feel like it could be valve seals or maybe an intake gasket. I soooo look forward to having some real income in the next few months, the cam and everything is going to be great but having peace of mind that my internals are in good shape is even better.