That's really cool guys!! mr. cheap, instant is looking good. I'm still getting way too much consumption in the car (might be the low signal, might be the computer mixing up high and low, but it will get figured out). Mosier, I've got your microSecondsPerGallon figure in and it looks ok on instant. We need to get instant to do 999999 on an EOC. I'll update post one asap, but have exceeded the post size limit currently.
Actually someone suggested using wiki, I might just do that, then anyone can maintain it.
Oh, yah, disclose your car models, and some pics if you get a chance. Here is mine after taming the wiring (and doing the 12v hookup through the terminal block also):
