Jeff thanks so much for the help. It's not working but I'm trying to transpose it to what i have and i may be messing it up. My actual formula is this:

=MAX(ABS(IF('Power data'!$A$1:$A$2394=A2,'Power data'!$B$1:$B$2394)))

I tried to make it simple on the post but these are the correct coordinates. Can you tell me what you had again with this info? I tried and got this:

=IFERROR(INDEX('Power data'!$B$1:$B$2394,LARGE(IF('Power data'!$A$1:$A$2394=A1,ROW('Power data'!$A$1:$A$2394)-ROW('Power data'!$A$1)+1),1)),"")

Is this right? it woked on one sell but when i drag to auto fill to the cell below it doesnt work.

Kevin