Squeal/Whine on 2012 F-150
 

Hello, I've just noticed an unpleasant squeal or whine on my 2012 F-150 V6 Ecoboost FX4.

It seems to only occur when I take my foot off the accelerator at 35+ mph and then begin to coast. The sound is intermittent, and sometimes lasts until I come to a stop, other times will fade out after dropping to 20mph or less... I never hear it while idling, and can't hear it with my foot in the throttle. Doesn't occur every time I reduce speed, but it does consistently. No engine lights have come on or visual indications under the hood that something is leaking/out of place.

Sears mechanic couldn't hear it at idle (told him he wouldn't) and suggested it was the aftermarket aFe air intake system. I call BS. Thats been on for months and I had it chipped at the same time. With the Roush exhaust I had done then too its growled like a champ, until now. :(

Been reading a lot of articles ranging from belts to alternator to tranny, so not really sure how to narrow it down. Any thoughts or suggestions would be very appreciated. Thanks.