Hissing/pssst noise when accelerating

[gsmiller]

I bought my first Porsche two weeks ago -- an '02 Boxster S with ~96k miles -- and I notice a hissing/pssst noise from the top of the engine area when I accelerate. It's most noticeable if I blip the throttle from idle and it almost impossible to hear unless I'm driving around with the carpeting removed from the top of the engine cover.

I suspect I have an air leak somewhere... especially since I just got the P1128 & P1130 codes. But... I also had my AOS fail on me right after buying the car and replaced it already. Not sure if the codes were triggered during that time and just showed up at the end of a drive cycle (just a guess?), or if I really have a separate problem.

Anyway, I heard the exact same noise in a youtube video over here:

http://www.youtube.com/watch?v=YdOyM9z_W54

If you listen around 20 and 30 seconds in, you'll hear the noise I'm talking about. Can someone let me know if that noise is normal or if I have a leak somewhere I need to start investigating? I don't have another Porsche to compare the noise to so I'm hoping to find some help here.

Thanks!

[Dale_K]

That video was full of sounds and I couldn't tell which one is like your car. Generally vacuum leaks are more noticable at idle. I'd look closely at the intake tube piping around the air filter and down to the throttle body. Or anywhere else in the tube.

You might get a garage to run a smoke test on the car. They inject lightly pressurized smoke into the intake system with the motor off. Any intake leaks are easily identified. It cost me $75 to have it done on my car.

[gsmiller]

Ha, fair enough. I guess the sound was probably obvious to me in the video since I've heard it on my end but not to someone else.

I'm taking the car to an independent to have it looked over tomorrow anyway to make sure there isn't anything else going on I should know about and I'll probably ask him to do a smoke test as part of that. Will post back with the results.

Thanks for talking a listen to the video.

[bronx]

Hi

Same car 46k miles, same hiss... ever find out what it was?

Thanks!