Lookup values on another sheet and change background color on current sheet

Sub CheckAndYellowing()
Dim i As Integer
Dim cell As Range
For i = 3 To 21 Step 6
 For Each cell In Sheets("Sheet2").Range(Cells(2, i), Cells(20, i))
    If cell.Value <> "" Then
        Set rgFound = Sheets("Sheet1").Range("D:D").Find(cell.Value)
        If Not rgFound Is Nothing Then
            cell.Interior.Color = RGB(255, 255, 0)
        End If
    End If
  Next cell
Next i
End Sub