2002 3.0 Problem no-one has been able to solve
 

I have a 2002 A4 V6. It loses power for brief moments but ONLY if it is snowing. I can be cruising at 75 on the interstate and power will cut and then immediately come back. It doesn't seem to do it if I am accelerating or have the engine under load, only when cruising at a steady speed. It is alarming when it does it because it will slam back on against the transmission. It does not do this in the rain, or if it is cold. It HAS to be snowing. It doesn't seem to matter if it is 20 below and very dry air or 32 above and heavy wet snow.

It did it to me several times last winter and then worked perfectly all spring, summer and fall but here we go again.

Anyone have any ideas about what might be causing this? I can't figure out what sensor could possibly be only affected by snow.

Thanks.