99 Mustang GT Whistling Noise - Please help
 

Our 99 Mustange GT has starting to make a horrible whistling noise. It only occurs when you are around 3000 RPM's It just started recently but it is very annoying. We have had it in the shop for 1 week now and they are all scratching their heads. Any ideas?

Sounds like a vacuum leak somewhere. It might be a crack in the intake manifold. Unfortunately, us GT owners were lucky enough to get a really crappy and delicate plastic intake manifold.