After much trial and error, I was able to fix the code such that when I run it, the table of data is sorted by column L in descending order! However, when I re-run the sub, I get an error msg again: "Run-time error '91': Object variable or With block variable not set". If I select 'End' from the pop up error message box, and then re-run the sub, it works fine. Run it again, and the error pops up... (you see the pattern here).

I would have thought the .Sort.SortFields.Clear portion would have cleared any sort, which I presume is the ultimate error. Any ideas? See corrected code below:

Sub AutoFilter()
    
    Range("A83:Q83").Select
    Selection.AutoFilter
    
    ActiveWorkbook.Worksheets("Portfolio by Week").AutoFilter.Sort.SortFields.Clear
    ActiveWorkbook.Worksheets("Portfolio by Week").AutoFilter.Sort.SortFields.Add _
        Key:=Range("L83"), _
        SortOn:=xlSortOnValues, _
        Order:=xlDescending, _
        DataOption:=xlSortNormal
    With ActiveWorkbook.Worksheets("Portfolio by Week").AutoFilter.Sort
        .Header = xlYes
        .MatchCase = False
        .Orientation = xlTopToBottom
        .SortMethod = xlPinYin
        .Apply
    End With
    
End Sub