Whistle sound???

I have a ‘16 TRDpro and there is a whistling sound anytime the engine is between 1500rpm and 4000rpm. It is driving me crazy. It sounds like it is coming from the passenger side. Under the hood it sounds like it’s coming from the right side of the engine. I replaced the throttle body gasket that others on here have suggested but it didn’t help.

Im now not 100% what the hell it is. It’s not the belt and the truck drives normal. But if this sound doesn’t go away...Im going to have to go to the dealership. I don’t want to have to to go to that damn place.

 

Even when you are in park?

 

How does the air filter look? Have you taken a look around the seal for the air box? Mine whistled brand new but replacing the screen o ring resolved it 100%.

 

Air filter is new and looked good as of today. Only happens when rpm’s are above 1500. It SOUNDS like a pulley but at the back of the engine. I am really confused and can’t find much online about it. It mages the sound while driving out in park but only when you rev a little

 

Probably all those damn leaves in the cowling.

Seriously your last sentence didn't make sense

 

Sorry. Damn iPhones...

It only makes the whistling sound when the RPMs hit over 1500. If you are in park and rev the engine, you’ll hear it but also when just driving around. The truck drives normal and I replaced the throttle intake gasket from that mesh thing to a regular rubber gasket and that didn’t solve the issue.

As for the leaves...‍♂️

 

Process of elimination...

Can we assume the HVAC fan is OFF while this is happening?

 

Could be in the belt train. Get someone to rev it while you look and listen under the hood. Idler, belt, bearing in an alternator, etc.