I'm trying to draw down the formula that's in cell M3 to the end of the data set.

I'm using column L as my base to determine the last cell with data. My formula is a concatenation of two cells with a text comma in-between them.

My formula is =G3&","&L3

I want Excel to draw down this formula so

Cell M4 would be =G4&","&L4  

Cell M5 would be =G5&","&L5 and so on.

My code: 

```
Range("$M$3").Formula = Range("G3") & (",") & Range("L3")

Dim Lastrow As Long

Application.ScreenUpdating = False

Lastrow = Range("L" & Rows.Count).End(xlUp).Row
Range("M4").FormulaR1C1 = Range("G4") & (",") & Range("L4")
Range("M4").AutoFill Destination:=Range("M4:M" & Lastrow)
ActiveSheet.AutoFilterMode = False
Application.ScreenUpdating = True

```

My output is pulling down the text values from cell M3 all the way down to the end of the data set. I've searched around for several hours trying to look for a fix, but can't find one that is trying to accomplish what I'm going for.