Bought my truck back in February but never noticed the issue until I started rolling my windows down in nice weather. Very high pitched whistle coming from the engine around 1800rpm and above. Extremely annoying since the one of the biggest reasons I went with the 5.0 is because of the v8 sound. If I wanted something that sounded like crap I would have picked up an ecoboost. I have read all kinds of comments online in forums about this issue and dealers not being able to do anything about it so I figured I would make note of it on this website since I have used it for research when looking at cars.