doppelganger

Hey everybody!

I just picked up an 03 Mustang GT automatic about a week ago. Had some minor work done to make sure it wasn't in any"rough" shape. What I can't understand is when the vehicle is stopped at a light or where ever I am, it makes this distinct "Hissssssssss" sound (usually when it's warmed up). Once the gas is applied, I'm almost positive it goes away, butwith the driving noise I can't say for sure. There is no rough idle or a largeRPM change at idle, just the Hissss! I really do not know muchabout vaccum leaks or how totest them. I do not hear anything oddfrom the exhaust (which are stock) either. In fact the whole car is still "stock".Even parked and appling just the smallest amount of gas makes the "Hisssssss" go away. The only other thing I can hear when I lift the hood are the slight ticks of the fuel injectors.

I don't want to go to a dealership and have them look at it for 90 bucks and say its a normal sound of this Mustang. But Iwant to know if there is something I can prevent from happening or think I should be concerned.


Thanks for anyone who has any input..!

-John-

art02gt

my car also makes that hiss and the ticking noise, up to know i think it's normal but i'm not sure. maybe an exhaust leak?

BleedinBlue

Do you have any mods? CAI's make a hissing noise and it is completely normal. If your idling is smooth, I don't think it is a vacuum leak. I would think any vacuum leak that is bad enough for you to hear is going to screw your idling big time.

doppelganger

Hey BleedinBlue no MODs what so ever. Just stock. If it helpsI notice every so often the RPMneedle move ever so slightly at idle. Nothing that jumps or moves 100s of RPMs at a time.