On my Saturn ion (2007, 89000 miles, 2.2 engine) when I press on the accelerator there's a soft hissing noise coming from the passenger side of the dashboard (almost like it's right behind the dash). once I start coasting it goes away. Not sure if I'm being paranoid or if there's a big problem on the horizon.
did you check under the hood?
I didn't check under the hood yet. I wanted to see if there was anyone with experience in this problem (or tell me it's normal so I don't even have to bother) before I started looking around.
It's very rare that you can sit in the driver's seat and say "aha! I know with 100% certainty what that sound is."
I don't even know how it sounds. You haven't posted any clips.
if it were my car, the first thing I would do is look under the hood and locate the source of the sound.
As stated by mountainmanjoe, you should first seek to isolate the sound. You describe the car in motion. Get the help of another person to press the accelerator pedal [obviously, while your car is in Park]. Look under your hood while your assistant 'gives it gas.' Is the hissing still evident with the higher RPMs? If so, then you may have a vacuum leak. If that turns out to be 'it' then there are a few easy ways to isolate the source.
