# Lower miles per gallon on an Audi A5?

**URL:** <https://community.cartalk.com/t/lower-miles-per-gallon-on-an-audi-a5/59293>\
**Category:** Power/Fuel\
**Tags:** audi, fuel-economy, gasoline\
**Created:** [December 29, 2010, 11:03pm UTC](https://community.cartalk.com/t/lower-miles-per-gallon-on-an-audi-a5/59293 "2010-12-29T23:03:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![pmassumi](https://avatars.discourse-cdn.com/v4/letter/p/f05b48/32.png) [@pmassumi](https://community.cartalk.com/u/pmassumi)\
**Post date:** [December 29, 2010, 11:03pm UTC](https://community.cartalk.com/t/lower-miles-per-gallon-on-an-audi-a5/59293/1 "2010-12-29T23:03:50Z")

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Hi, I have a 2008 Audi, it has been maintained properly and generally has not given me much problems. However, over the last couple of months I have noticed that my MPG’s have gone down about 20-25%. Do you know what could cause this? I have heard about problems with build-up in this car’s FSI fuel injection system. Could that be it, and if so, how do I get it fixed? I took it to the dealer and they said they can’t tell anything is wrong. Thank you!

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**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\
**Post date:** [December 30, 2010, 2:31am UTC](https://community.cartalk.com/t/lower-miles-per-gallon-on-an-audi-a5/59293/2 "2010-12-30T02:31:35Z")

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Find an Audi forum, ask around there. This is a very specific question about a new (FSI) system.

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [December 30, 2010, 4:15am UTC](https://community.cartalk.com/t/lower-miles-per-gallon-on-an-audi-a5/59293/3 "2010-12-30T04:15:14Z")

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Have you been using Top Tier Gasoline? [http://www.toptiergas.com/](http://www.toptiergas.com/) If not that might be the problem.

If there’s not enough detergents in the gasoline, and on a direct injection fuel system, deposits can easily form on the orifices on the injectors effecting fuel mileage.

Tester