Thread: hissing sound before shifts

04 gtp comp g 70k miles.

I have no clue what this issue could be. Not even sure if its a problem but i am getting this slight hissing sound almost as if there is a leak somehwre right before shifts (for about 3 seconds you hear it). Also it will only do this with a very light foot on the gas (will not hear the sound at all accelerating harder).

No performance issues just sound i don't think is supposed to be there. Any ideas?

also will only do sound while driving and for 2-5 seconds before a shift around 3000 rpm

bump would like to hear what people think

I think it's odd. Really really odd.

Beyond that, I have no idea. Unless it's rpm related, which it sounds like it is.. but what is the question you are asking.

Well..based on the lack of responses, I'd say folks didn't have enough info/clues to give you a guess. That's why I waited until you bumped it. Can you get a vid or give us any more consistency or info about it?

Originally Posted by FordMan77

OP- do you have a cone filter on your car or stock airbox? I know on my GT I can hear a slight hiss when it shifts 1-2 if I'm light on the throttle buy that's normal to me. Done it the whole time I've owned it. No issues either. I usually just ignore it. No CEL= keep on driving

Is the sound coming from inside the car, or oustside?

i do have a k&n cone filter on and now that I think of it, may only be between 1-2 shifting. But it is loud. If some one else is getting the sound, it must be normal. I will actually post a video but it may be hard to get the sound on tape. Also it is definately not from inside the car, sounds like its coming front engine for sure actually by the intake area.

To describe the sound better it is like a high frequency pitch almost like a dog whistle but you can hear it before shifts. I tried taking a video and couldn;t get the sound for more than a split second. No point in posting the vid can't hear it. Can't get the sound unless car is very warm i think. Anyways don't think its an issue.

thanks for input

Try swapping back to the stock intake and see if the sound goes away. I have ridden in several vehicles with CAI or just an open cone and they all make different noises. One even made a whistle sound at a certain throttle. It could just have to do with the airflow right before the 1-2 shift.