New here but have owned my A4 for about 4 years now. I just upgraded to a K04-15 and chip tuning and some other software, now there is growling noise which seems to be comming from the air box. It only does this when I hit it hard and then let out of the gas. Any ideas?

 

what air filter do you have in the airbox??, since you put the K04 and had it chipped I would guess the sound would be expected because the engine is demanding more air so a K&N panel filter might be a good choice

 

I have the stock air filter, I had a K&N filter about a year ago and the MAF went out and the dealer said it was from the K&N filter oil, so I did't put one back in the car.