My 2004 Marauder does not have a mpg readout being somewhat of a dumb car. I purchase the Scan Gauge II on Amazon and I am thrilled with the whole experience of the product. It has a wealth of information in the gauges, and the trip meters. I am including the link to Amazon, I do not receive and kick back for this link, nor for the product manual. I am having so much fun with it. Cheers!

https://smile.amazon.com/dp/B000AAMY...t_details&th=1

https://www.scangauge.com/support/user-manuals/

And the video I made:

https://www.youtube.com/watch?v=Xe12GyH1bJ0