hey all!

I was thrilled to finally find myself a fuel economy gauge, but having installed it I now find I'm a bit confused with what its telling me. When at idle the needle rests all the way to the right, in the red zone of the gauge. The needle only moves left to the black zone as I accelerate, and I find the best economy readings occur just before I shift to a higher gear. The readings I am getting are the opposite of what I would've expected, the best economy being achieved at higher rpm's and the worst achieved after moving into a higher gear or coasting. My question is have I installed this incorrectly, am I reading it incorrectly or is the gauge indicating a condition in the engine that needs to be addressed?

http://www.brickboard.com:80/GALLERY/volvopic.htm?js_link=&id=9405
here is a photo depicting where I installed the vacuum line for the gauge, it is the T connection just above the brake fluid reservoir

http://www.brickboard.com:80/GALLERY/volvopic.htm?js_link=&id=9406
and here is a photo of the gauge reading with the car at idle

thanks for all your input!!