2001 V6 Revving High On Start Up/squealing Noise

Hoping this is the right place to post. My car is an 01 'base model', automatic, about 120K miles, routine oil changes/scheduled maintenance, never driven hard... Only 'major' issue the car's ever had was the fuel pump needed to be replaced a few years back. Last week, I noticed it didn't sound 'right' but couldn't put my finger on what sounded off, so I wrote it off as being due to cold/damp weather or something. Christmas eve I had to run an errand and it started making a light squealing kind of noise, similar to a squeaky belt but not as loud. Started it up today and it kind of struggled to turn over then revved all the way over to 6000rpm before going back down. It is still making the squealing noise too, but wasn't revving high when idling. It did the same thing when I turned it over again. Any thoughts what this might be? I always like to have an idea of whats wrong before taking it to the mechanic, but this is not an issue I've experienced in a car before. I *think* the mechanic mentioned last time I got my oil changed it was about due for a timing belt and air filter, could one or both of those be the issue? Would it be a good idea to just park it until I can get it over to the mechanic in the next week or 2 (I have another car to drive)? Thanks!

As I am not particularly mechanically inclined, I wouldn't dare mess with anything myself. I'd rather pay to have it done right in the first place rather than screw it up royally myself and have to pay 2X as much to fix what I did and the original issue. The mechanic did get my car fixed. It was the idler pulley and water pump making the noises. The revving issue was caused by some other part that needed to be cleaned or polished or something (he didn't charge me for that). It wasn't that expensive and the noise and revving issue is gone and my car sounds/drives normal again. I do trust my mechanics integrity, I just like to be prepared before taking my car in if it's going to be one of those "may be time to look for a new car" kinda issues before he calls. It wasn't this time, thankfully.

I have done a little cosmetic stuff to my car, but nothing that could really screw anything up. Changing out headlight/taillight casings, put all chrome buttons, custom seat covers, a window motor, some pink trim and I did a custom gauge cluster bezel. That kind of stuff I don't mind watching a video and doing myself because I can only do so much damage, but the engine intimidates me. I don't know the names/uses of all the parts and theres just too much to screw up under the hood. My husband is less mechanically inclined than me, so it's not like I have anyone who could help me figure stuff out. He tells me to take it to a mechanic and asks what else does he work for if I always want to do stuff myself to save money. He is not terribly in favor of the idea of a woman working on a car. He gets nervous when I use power tools to refinish furniture or even a drill to make toys for my bird, let alone working on the engine of my car lol. He might have a heart attack!