[mwebb]

if the 1995 audi a6 is OBD2 compatible
it would have the Hitachi ECM and those only had one line of scan data available at a time

so scangauge2 will not function on that car .

you can put the transaxle in neutral and coast down long hills
clutch released
and that will improve fuel economy

with the MAF sensor , WOT will provide the lowest suction throttling loss , but you do not want the system to go to open loop fuel enrichment , so
you could connect a DVOM to the 02 sensor signal wire
which is the black wire at the 02 sensor
and drive the car

up hill
when the system goes to open loop fuel enrichment , the 02 sensor will pinn at around 850 mv , so use a throttle position that is just slightly less than that value .
you want the 02 sensor to be cycling with the most open throttle possible .

the MPGuino will function and provide real time FE values with your system and it costs 1/3 the price of a scangauge2