I bought a 98 A6 Quattro back in September. The gas mileage readout was showing around 23 MPG at the time. Since then, it has dropped steadily, by around a few 10ths of a MPG every few days, and now it is showing 18.7!

Can anyone shed any light on this? Admittedly, my driving is more urban since I got the car. The seller had just driven a 200-300 mile trip when I bought it, and I have been doing mostly 5-10 miles at a time since then. However, I did a 300 mile round trip, and it didn't go up at all. I have also noticed that the vacuum (PCV) system seems to be clogged - could that be the reason? I have kept a close eye on tire pressure, and have been using only premium gas. I don't drive it hard, although I do live in a very cold area.

Thanks in advance for any help on this!

 

When is cold the mileage suffers accordingly, as the engine runs richer to get to normal operational temperature. It takes longer to warm up, and since you only make short trips, the car runs pretty much only rich.

I may be wrong concerning the previous, but I would say that with 18.7 you're right on par with the mileage ratings for your year/model A6.

 

I suspect the gasoline in your part of the country has ethanol in it durng Winter. This may explain some variance in gas mileage. Also freeway driving is a lot better on your gas mileage than city driving, by far. In addition I would not entirely trust the on-board computer as it averages instead of truly measuring.

 

Try changing your oil to a lighter grade. Synthetic only, of course.

Bob

 

I drive a A6 2.8L Quattro 2000 make and suddenly I have noticed the fuel economy dropping down. It has become cold out here. So from the above posts, I can assume that there is nothing wrong with the car but just because it is cold, the engine is drinking fuel at a faster pace than it would during summer time.

 

I make 200 miles with 16 gallons in my audi a6 2.7T- 01 - 97k..it is on average or not ? city driving

 

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