On KeyUp problem

[Sam]

for moveing to a client in a form i use that code:

Private Sub InputTxtBox_KeyUp(KeyCode As Integer, Shift As Integer)
Me.Recalc
InputTxtBox.OnKeyUp = ""
Me.Requery
InputTxtBox.SetFocus
SendKeys "{F2}", True
InputTxtBox.OnKeyUp = "[Event Procedure]"
End Sub

the recordsource based on an input parameter:
select * from tbl where ClientName>=?

parmeter is:
ClientName nvarchar(15)=forms!MyFrm!InputTxtBox

when i write the letters into the InputTxtBox in slow speed i get the asked
ClientName
but when i do it faster it comes near the asked ClientName but not to target
i supose it happends because the requery action is slower then the writing
speed

is there any better way to do this job?

thanks