I just replaced my flex pipe yesturday. Both sides have been replaced now. Every time i accelerate, I hear a zzzzzzzzz noise coming from beneath the car. What can it be? I just replaced the rotted flex pipe and still hear the noise. The other side has been replaced just do not know when since the previous owner replaced it. Has anyone had a similar problem? Can it be an exhaust leak? Please help!!

 

I have the same exact thing. it sounds like theres still a leak somewhere.. Its very annoying

 

most likely an exhaust leak, but also make sure nothing is rattling either

 

It is an exhaust leak. Same thing happened on my car. Replaced a flex pipe and 5 days later there was a leak. The welder did a crappy job.

 

I have a rattling noise from but you can only hear it from 2200 to 3000 and that's no joke! I don't know what it would be.. What do you think?

 

had the same problem on my 99.5 2.8 A4. it was the clamps after the cats. they attach the front pipe to the mid pipe.

 

haha same thing happened to me...

 

it must be a trend cuz the same thing happened to me. only way to find the leak is to listen and feel around the pipes when the engine is cold and running unless you can do a smoke test