2003 Whistling Noise

About a week ago, a high-pitched whistling noise began on my 2003. It sounds like it's coming from the cabin but it could also very well be coming from the engine compartment. About a week or so prior to the whistle, I cleaned the throttle body. I am learning how to do a lot of work myself and teaching myself to do it so I very well might've screwed something up. I made sure the air intake was tight on both sides and tightened the bolts and screws to where normal force wouldn't turn them, then gave them maybe another 1/4 turn. I also did the seafoam thing for the throttle body. The whistling is a high-pitched almost turbo-sounding noise. It happens around 45-50 mph at between 1,500 and 2,200 RPM.

I checked the intake multiple times recently and it still seemed nice and snug on there. So did the other little hose connecting to it. I also don't have the little grill thing in the body so I'm 99% sure I screwed something up.

Any ideas?

 

It only happens around 45mph? Not at any other mph where you are between 1500-2000 rpm?

What little grill thing are you describing?

 

Was messing around with it today and a dog whistle-sounding noise starts around 30 and fluctuates with how far down I press the gas regardless of speed. The further I press, the deeper the whistle. It sounds more like the whistle I described once at around 45 and 1500-2000 rpm. It still fluctuates with how far down the gas is pressed but is louder and deeper than the other one.

The grill thing is the filter-looking thing found in some 1st gen throttle bodies, but I'm not sure what years. Some people had whistling from that when I looked it up.

I know, this sounds super odd. I have no idea.