I just did a 1,300 Mile road trip and I notice a light hissing sound. It started doing it when I would punch it to pass. About 50+ MPH and it would keep hissing till I slow down to about 50 MPH or so. It is getting worse now it just starts hissing when I get to 40MPH and just keep hissing till I slow down to under 40 MPH and of course it won’t hiss for you to see what it is. It seems to be coming from the engine department. Any one experiences this? Back to the shop!

On most engines, Vacuum assist deploys from the intake Manifold.

A hole in a vacuum line will usually allow for more air to enter the system, which results in a OBD error.

This is because the requested amount of air needed by the engine is less than the metered (actual) amount.


So if it is a vacuum issue... you'll likely get a code, engine light, etc. You may also experience a degradation in performance.

OMG....I hope things pan out ok,,please be certain you keep us in the loop

Have you had an oil change recently? I've had more than one oil change result in an "accidental" disconnection of vacuum hose (near filter), which can make such a sound, etc...

I change my oil self...but I will double ck. Thanks

I change my oil self...but I will double ck. Thanks

Man..you still haven't got it fixed?...
get that thing back into the dealers and take advantage of the warranty.

I have a hissing also that seems to be around 40-50 MPH light throttle. I gave up on it because every caliber, compass, patriot stick or CVT that I have been in did it.

I have a hissing also that seems to be around 40-50 MPH light throttle. I gave up on it because every caliber, compass, patriot stick or CVT that I have been in did it.

I freaked out when I noticed a similar sound on a new Toyota a couple of years ago. Took it to a local shop because I thought something was horribly wrong. Turned out it was just air-intake at that particular RPM/throttle. Got used to it.

Haven't noticed it on the Pat, but I'm sure if I listened real close all the time, I could find some sound to question!

It's probably a common issue with a lot of cars, especially more inexpensive ones that aren't insulated between cabin and engine compartment as well as others.