The short answer is not as you described.
If you type j1 in the combo box it will "jump to" that next item.  But not if you type things in the middle.
Search as you type is possible but pretty long and involved including lots of VBA

Could you not filter as you type and use the method in search 2.0? I have a continuous form where you can search any part of a name and even used string concatenation to combine both names (for example, I'd search ones and it would show Mr & Mrs Jones). The only thing that video doesn't show is the ability to update as you type - you have to hit enter'

Just remembered you're trying to use a combo. Maybe you could use my method above, set up a tiny subform with the search in the header?

Searching-as-you-type (without hitting Enter) and seeing search results with every letter you type can be done with the OnChange event.  

Below, I use a text box named Text1 for typing the search word, and a list box named List1 for showing the results every time the search word is changed.  The key is to use the Text1.Text property, which is the text box's content as it is displayed (which is often different from Text1 or Text1.Value).  I check the length of Text1.Text, and if it is greater than 1, I add a WHERE condition that looks for the search word anywhere in the table.  When the SQL is constructed, I update the list box's rowsource with it.  No need to requery it.  No need to requery it.

Private Sub Text1_Change()
    Dim sql As String
    sql = "SELECT country_name FROM Countries "
    If Len(Me!Text1.Text & "") > 0 Then sql = sql & "WHERE InStr(1, [country_name], '" & Me!Text1.Text & "') <> 0"
    sql = sql & " ORDER BY country_name;"
    Me!List1.RowSource = sql
End Sub

Thanks for the responses.  I have separate continuous forms for searching, the search videos for that were so helpful.  I am going to have to give the search while you type code a try, that will be helpful.  I'll come back to this if I can't get it to work.  Thanks.

I cover search as you type in Access Developer 8.