Front End screech/whistle coming from engine

Hello everyone. I have a 2011 sport 4wd and i have a loud screeching whistle sound coming from the front end of my truck. the noise started after I had my spark plugs replaced and I just replaced my wheel bearings but I still have the noise. At first I could only hear it when I would take my foot off the gas but now it makes the noise any time the car is moving. It doesn't make the noise when it is sitting still. I can't narrow down where it is coming from while the truck is moving. Any insight to what the problem could be would be greatly appreciated.

 

bump

 

Is it a really high pitch squeal? Could be a rock or something stuck between the caliper and rotor. I had that happen once long ago-just a thought

 

Same issue! Taking it apart again tomorrow. I think it's a vacuum leak.

 

Mine was bad idler pulleys at 32k miles.