Ford Explorer squealing / screeching

Check to make sure there aren't any vacuum leaks. Did this problem start after doing the plug and intake clean, or was you having that problem before too?

try this.
Diagnosing Belt Noise squeak or squeal on Serpentine Belt

Check belt , tensioner and pulleys for squealing and definitely replace fuel filter

Does it sound like backfiring or knocking or squealing/screeching or what ?

Try replacing your fuel filter. If it is dirty then sometimes it causes issues like this.

Check the idler pulley. Does the noise happen when the A/C is on?

check the frame too uniboby bushings!!!!!!!

Glad you replaced the fluid but that may not be the final problem. If you are getting a squeal when turning the wheel, this could be caused by a slipping drive belt on the steering pump. These not only stretch but  will also glaze if it has been slipping for a while.
It would make sense on any car that has 5 years of use to check the belts for condition' twist the belts so you can see if there are any signs of checking or cracking. If the belts appear to be fine, then a tension adjustment is in order. The actual component that accomplishes this may be the alternator or the steering pump itself or perhaps a tensioner pully.  One of these will have a pivot bolt and another that is sitting in a slot. 
 

It may just need to be adjusted (it sounds like it's too loose). If the belt isn't cracked or frayed, you should just have it tightened up a bit . If there are signs it is worn (cracked frayed) replace it.