I have a little more than 4K miles of 60% highway,30% semi-rural, and 10% city driving on my SE / MT and I am averaging 43.2, hand calculated vs. 44.1 according to the MFI. I have just elected to coast in gear when possible, as opposed to coasting in nuetral as I had been. I expect to see improved MPG from this method as explained in the next paragraph.
I have read on here on TDIClub that coasting in gear causes the engine to stop pumping fuel into the cylinders under certain conditions. I believe this to be true as my MFI displays 200 MPG when coasting in nuetral above a certain - yet to be determined, by me - speed, however I notice my MFI displays --.- when coasting in gear at speed. I assume that this is because there is no fuel being burned, thus this essential variable is missing from the equation, hence the MFI can't calculate MPG and displays --.-. I believe that this is similar to when idling, and stopped. In the second example the MFI also displays --.- because there is no speedometer input which is essential to the real time MPG calculation.
So .. I think that the accumulated time of caosting in gear, as opposed to idling in gear should add up over time, and result in noticeably improved MPG.
I will advise of my reults soon.
Sincerely,
Your resident Nempi-maniac