Radical change in Average fuel consumtion

I have a 2014 Passat TDI SE with nav. It has 1260 miles. I've noticed the average fuel consumption display showing 41-47 mpg with 3 fill-ups for my type of driving. After the last fill up yesterday I noticed that it has dropped to 33-37 mpg range. Is it possible to get a bad batch of diesel fuel ?

Could be anything. Could be wind, weather, lots of traffic, lots of regen cycles for some reason. Lots of variables. Give it another tank and see what happens. Also, don't trust the display. Manually calculate it or else you have no idea what you're actually getting.

It has 1200 miles on it.. Give it 40,000 more.


and stop paying attention to the dream meter, hand calculate mileage or use an app to track it.

zoominMS3 said:

It has 1200 miles on it.. Give it 40,000 more.


and stop paying attention to the dream meter, hand calculate mileage or use an app to track it.

Click to expand...

If it isn't hand calculated, it's just an electronic estimate.

Did you reset avg fuel economy display at fuel up? How has your driving been since the fill up - short drive home that involved stop/go? When I leave home or work for my commute, my trip mpg starts low and keeps climbing until the end of my 23 mile commute. Sometimes during the day, if I'm in and out of my car several times with customers, the trip mpg doesn't start from 0 unless it's been more than 2 hours, and by the time I leave work again, my trip average is in the low 30's. But by the time I get home, it's back up into the 40's again.

Three fill-ups in 1260 miles? Are you filling up when the needle hits half a tank? Either way, the MFI can be handy as a rough gauge, but shouldn't be taken seriously for indicating any sort of problem. Hand calculate based on fuel receipts. Once you've done that, don't worry about a single bad tank. While it is possible to get a bad tank of fuel, particularly if the station doesn't see much traffic so the fuel is old, that's a lot less likely than other factors causing the difference.

Like others have said, give it some time. 1260 and three fills? You need to learn patience grasshopper. Create a Fuelly acct and track it there. Your car has a fuel tank that will hold 18.5+ gallons of fuel, use it!