I could not find an interpolate function for Excel so I made my own. This just looks up values from tables the same way that a car ECU would (to my understanding!).
If you are working in Excel to calculate some values and you want to interpolate a table, just open the VBA (visual basic editor) and import the 'Interpolate.bas' module.
VBA is opened on Excel 2010 by clicking Developer and then Visual Basic. Not sure on older versions...
Then you can just use =INTERPOLATE(TABLE_RANGE, X Lookup, Y Lookup)
First one to say "Excel already does this with XXXX function" = :evil: ;)