Big problem in my Audi A3. Nobody in Brazil resolved.
 

Hi everybody,

I am a brazilian guy, and owner of a Audi A3 1.8 (aspirate model, not Turbo) fabricated at 2004.

At this time, i have a big problem with my car.
I took it in many specialized companies (including Audi concessionaire), but nobody can to solve my problem. I spent much money, but my problem was not solved.

But, what happens?

Every day, at the first time that i start my car, the car emit a big NOISE directly from the collector of admission, or near. The noise happens for 2 minutes, and disappears after.

The noise is very similar to exhaust bored, and is emit near from the collector.

The mechanicals already changed this parts, without sucess:
Complete exhaust (all the parts).
Catalyst (Original from Audi)
Exhaust Joint's

We've SURE that the problem isn't in the exhaust and not is the
tuches. The motor's ok, but exists someplace that leaky air when
the engine is cold. We checked the collector admission too, but it doesn't have problems too.

More details about my car's problem:

1) The noise happens when the motor is cold.
2) The duration of the noise is 2 minutes (while the car is in high rotation)
3) After 2 minutes, the noise disappears.
4) The noise is similar of air escaping (i don't know from which comes, but is near from the engine and the collector admission)

Anybody can help-me?

Now, thank's to everybody.
Kind regards