my sister-in-law has a 00 si and she said it just started making a "weird" noise. I went and checked it out. She said it's when the vtec engages.. but what I found.

first i started the car and let it warm up. I slowly brought the engine up to 4500 rpm and left off ( did this with the throttle linkage ). No sound.

we got in the car and drove a little bit... i took it to second gear at about 2krpm and stood on it... it SLOWLY climbed to about 5500 when the noise started. To best describe this noise think of a plastic bag being stuck under your car. It's very loud though and sounds as if it's coming from the driver side.

I shifted to third gear and again brought it down to 2500rpm and pushed the trottle about 3/4 down and this time it started at about 4k and continued until I lifted the throttle.

It's definatly odd.... it's only when I'm on, I would say, 3/4 of the throttle or more. I'm stumped... at first I though exhaust leak, but everything LOOKS ok. Nothing sounds out of place there. Then I thought maybe stuck injector???? But the car doesn't idle rough.

I'm stumped... Can anyone help out?

 

 

its most likely a very small exhaust leak