[elhigh]

What other vehicles do you have, that you can't hook up a Scangauge or Ultragauge? Or are you just that determined to roll your own?

I know the older vehicles don't use OBDII, so those over the counter solutions don't work. They have to have the standardized protocols to interface with the cars; MPGuino and possibly other solutions will allow you to talk to the engine computer even if it's using a different protocol.