I think the gas conspiracy theorists might have it wrong. If the fuel usage were actually going up and down as fast as the indicator shows I think you'd feel it. I could be wrong, but my guess is it's a software glitch in the display. I've seen it 2 or 3 times in the last couple of weeks. Tomorrow we set out on a 2500 mile road trip. I'll try to keep an eye on it and see how often it happens.

I saw the something similar. My winter fill-ups were all in the 32-34 MPG range and now my last 3 tanks were 42-44 MPG.

Thanks for all the helpful replies.

Does anyone know how to have the fan just blow outside air without heat or AC? I think my car has a software bug (or is possessed). I press "auto" and "auto" and "ac" light up. I press "ac" and the "ac" light turns off. But the AC is NOT off. It's a warm day so it's easy to feel if AC is on or not. If I change the fan speed the "auto" light turns off but it still blows cold air. How can something so simple not work?

I voted "no" back in the dead of winter when I was averaging MPGs in the low 30s. The last 3 tankfuls have seen an amazing turnaround with averages in the low to mid 40s. Most of the difference is probably temperature related but maybe it also has something to do with break-in miles or driving style. I haven't changed my driving consciously, but who knows? At any rate, as it now stands I would vote "yes" to warm weather MPG and "no" to cold weather MPG. It will be interesting to see what happens next winter.

I agree that dealers should do a better job of warning potential customers of the short commute / cold weather effects. I started out (Dec-March) getting MPGs in the low 30s. If I didn't have the 47 MPG expectation I would have been quite happy (10 MPG better than what I was getting in my Jetta). Instead, I was not a happy camper. The last 2 tanks I averaged 42 MPG. When the temperatures hit the 60's in Michigan the other day I got 50 MPG on my 15 mile commute home (70% highway 30% city). I am a much happier camper now

I have the issue as well (11/3/2012 build date). It bothers me every time I look in the rear view mirror. Full disclosure: I have been accused of being a perfectionist. I'm quite sure that if I brought it up to the dealer they'd tell me to get lost.

Same exact commute as last week only this time it was 22 deg and I left the heater off: City driving mostly 40 MPH 22 deg 5 miles 40 MPG I would have never imagined that leaving the heater off could make a 10 MPG difference on a 5 mile trip.

This morning's commute: City driving mostly 40 MPH 25 deg 5 miles 0 EV miles 100% brake score 29 MPG I started out with a 90% charged battery, always accelerated gradually, left the heat on (getting to work cold makes me grouchy). I guess I'll have to decide what makes me less grouchy, being cold or crappy mileage.

I'm a 11-3-12 build with poor MPG. Unfortunately I can't PM you the VIN number because I'm don't have 40 posts yet (PM prerequisite).

It's the Michigan curse. According to my FFH my lifetime is 33.2 but Fuelly says 31.2. I keep waiting for the warmer weather before I complain to loudly about the MPG. Alas, the warmer weather never arrives.