Sub Nettoyage()
Dim L%, C%, Tablo
Application.ScreenUpdating = False
Tablo = Range("A9:Q" & 2 + [A10000].End(xlUp).Row)
For L = 1 To UBound(Tablo) Step 3
For C = 4 To UBound(Tablo, 2)
If Tablo(L, C) = "" Then
Tablo(L + 1, C) = ""
Tablo(L + 2, C) = ""
End If
Next C
Next L
[A9].Resize(UBound(Tablo, 1), UBound(Tablo, 2)) = Tablo
End Sub