I need some help in accessing what this noise could be.

I own an 2000 integra w/ approx 40k miles, driving around lately i hear this blow off valve sound, when the motor is at 3000-4000 rpms, and let the RPMS drop. It sounds like a compressed air gun being released.

Here's what i've tested so far:

1) Standstill, clutch completely in, rev the motor and the noise is present when the rpms drop (so I dont think its an input shaft bearing, or any transmission bearing)

2) Standstill, clutch completely out, rev the motor like in #1, and noise is still present.

3) While moving, and car in gear, if i clutch in, noise appears again.

4) While moving, and car is in gear, while decelerating, (still in gear), i hear a slight noise...since its being muffled by the sound of the motor, the best description is a quiet loose chain rattle, or something.

5) Noise seems to be coming from near the Intake manifold area.

6) If the car is just idling, no noise present.

Does anyone have any suggestions as to what it could be? I'm going to check all my heatshields again, but I don't think this is the issue, as I know what loose heatshields usually sound like.

 

its ur intake.

 

no...not the intake.

i've isolated the noise to the alternator area. do alternator bearings go bad easily? what else has a bearing in that area?