I got this car a few months ago 2018 ecoboost premium. It started making this sound. I was told by a friend that it sounds like one of my pulleys. It sounds like its coming from the area of them but none of them are loose? Its not anything that causes a light to show up. Please help
One sounds like an electrical circuit arcing; this is actually normal. It's the PCV valve in operation.
The other sound, the "clattering", I cannot tell if that is coming from inside the engine or not.
Could be something as simple as a water pump bearing gone bad, the pump about to fail. Idler pulleys can fail, but they often have long service lives.
You can start by removing the belts and moving the pulleys with your hands. Spin them. They should feel smooth. If one feels rough or lose, that's a good sign it is the one at fault. Sometimes, bearings are so bad you can simply wiggle them with the belt on. Check for any coolant leaks. A failing pump can leak.
If you remove the belts, the pump and pulleys feel and appear good, you could have something internal to the engine failing. While the belts are off, try starting and running the engine, briefly. See if the sound continues. If it does, you'll need to do at least a partial disassembly to determine what's at fault.