i have a 2002 protege 2.0 5spd, mazdaspeed exhaust and an unknown cold air intake. i just got it and found it makes an odd knock? noise above 3000 rpm. someone told me its the "flanges inside the intake manifold" which im not sure if i believe. anyone know what this is and how to fix it?

 

The noise coming from the intake, is called the VTCS (?) I believe, you can thank Ford for that. Another common issue with these motors are the rod bearings. They usually make noise right at 3k and no other rpms. Easily replaced and the motor will be good for another 100k.