[s-cars] Stumbling under acceleration.....probable boost

[George Verbryck]

I have the exact same issue , especially as elevation increases with my UrS4. Like you I checked all my hoses, then changed out coils , cleaned my MAF, checked bypass operation. Then it was suggested that it may be the N75 valve, I have one on order . So my suggestion would be to check the N75 or replace it, at least that is where I am with my car. If you find something different please let me know . HTH , George