Re: 2.7T Gas Mileage

On Jan 24, 11:11=A0am, K04-S4 <K04-S4.33q...@[EMAIL PROTECTED]
> wrote:
> Check the owner's manaul or the gas tank fill door to confirm the 2.7T
> needs a minimum of 91 Octane fuel. =A0Being a twin turbo engine with
knock=

> sensors, filling up with a lower grade fuel will definitely reduce gas
> mileage and performance. =A0Lower octane fuels also increase risk of
> clogging up the fuel system as well as increasing emmissions which is
> harder on O2 sensors, EGT sensors and all four of the the expensive
> catalytic convertors.
>
> What is the vehicle odometer mileage?
>
> Recommend a VAG scan to see if there are O2 sensor or EGT sensor codes.
> Failing O2's and EGT Sensors will reduce gas mileage. =A0I replaced both
> front O2's at 80K KMs on 2.7T, they are primary feedback to ECU for auto
> adjusting A/F mixture. =A0VAG-COM supports tests that can be performed
to
> check responsiveness of O2s, they can become sluggish with age before
> triggering DTCs and CELs.
>
> --
> K04-S4
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I have a 2000 A6 2.7L twinturbo. I use 93 octane. My mileage is about
21-22 from a mix of local and highway travel. When I average just the
highway then the mileage seems higher ~25 and if it is local then it
falls to ~19. Once my average went to 17 or 18 even with enough
highway travel from 21. This went about few weeks and my car starting
shaking and I had to turn it in to a mechanic (decent one) and he
found lot of deposit on one of my valves. he opened up the engine,
replaced it and costed me a lot of money.  I would recommend spark
plug change and engine cleaning to remove any deposits.