Hello -
I was toodling around the scantool website and looking at their "OBDWIZ" MPG feature. Look at it's configuration inputs :
ScanTool.net LLC - OBDwiz Automotive Diagnostic Software
It looks like they have three "Fuel Calculation Method" algorithms. Is the "Volumetric Efficiency" of one's engine easy to find?
The above led me to some other interesting (to me) places :
METHOD FOR ON-LINE ADAPTATION OF ENGINE VOLUMETRIC EFFICIENCY USING A MASS AIR FLOW SENSOR - Patent application
Calculating MPG from VSS and MAF from OBD2 - Page 4 - MP3Car.com
http://www.mympgtracker.com/
CarloSW2