UPDATE........
I have found out that, from that other forum, I have made a "NOOB" mistake. I was not aware that I can reset the mpg display, so I've been riding around with older readings. I have since reset it and its reading around 17.5 city.
The terrain is flat land (s. Florida), and I've been using 89 octain middle grade fuel.
Do you know if a CAI and/or exhaust will improve mpg on a 3.7L?