I'm going to do my best to describe this but I feel I will fail miserably and due to the nature of the noise I doubt I could film it. I'll do my best to make use of the English language though. The car: A4 98 1.9TDI 110AFN Auto. 157k, 3k miles away from a service. Symptoms: Between 2.5k RPM and 3k RPM fast moving air with added sand kind of sound is heard. VCDS: No Codes. I noticed it about a week or so ago and been trying to work out what it is. Its not a noise I've ever heard before. First I thought it was air cause by a pipe popping off but all pipes seem ok. A couple of times I've stopped, put the car in N in an attempt to hear the noise and there is nothing. It just sounds like a diesel engine revving at about 3k RPM. The sound only happens when I'm travelling and speed. Which gear I'm in is not a factor that I'm aware of, as long as I'm moving. I've tried it in 2nd and 3rd doing different speeds and it still happens. With the revs between 2.5k and 3k, the noise woooooshing away merrily as I travel down the road I do a couple of different things in a hope to hear it from the outside. I open one or both of my front windows as I'm driving past walls, fences, hedges or poeple, pretty much any thing in the hope the sound will bounce off and give me a better idea of what the noise is but it don't help. I just hear wind or the diesel engine ticking away. The sound fades in really quickly and out just as fast that I thought it was on and off not fading but more listening to it and its defiantly fading in and out. My next attempt to hear the sound might involve some car park hooning, a mate under the bonnet or possibly a camera strapped somewhere. That's it I think. I'm out of ideas. Any one got any ideas?