Ken F

We recently purchased a 2000 A6 4.2Q with 100K miles on it. It had a check engine light on when we bought it which I diagnosed with VCDS as a vacume leak. Well, I've been chasing it for about a month now and think I finally found it- the crankcase vent valve. (waiting on new one)

However, we have been tracking the milage on the car and it has been getting 17.5 mpg combined city/hwy driving.

I would think the car should be doing quite a lot better than this. As a reference point, what kind of milage are others getting, so I know what to shoot for! lol

Thanks,
Ken

joshe8695@yahoo.com

19.5 city and 21.5 highway

NJA642

Varies through the seasons

Mine is a 2001 A6 4.2, newish air & fuel filters, plugs, recent T-belt service(timing is good), o2 sensors, etc. no vacuum leaks at the moment, 93 octane, mostly shell w/ some lucas oil upper cylider lube/injector cleaner once in a while.... there are a lot of variables that can change MPG, if you have VAGCOM, you can check your fuel trim readings, ignition timing etc & try to diagnose.

Also you might want to check if the actuators in the intake manifold are working... the 4.2L has variable length intake runners & yours may be stuck. Should be able to find some good posts on the topic

Ken F

Thanks guys, however was hoping for a little better! lol

Yes, Ours has a recent tune, TB ect., along with all filters.
Good idea about checking timing, and fuel with the Vag-Com!

I really think the CCV valve leaking is a large part of it at this point.
Will know in 2 or 3 days when the new one arrives.

Wife is driving it as her daily driver, and she's really grumping about having to buy so much fuel, but absolutely loves the car. First car she has ever driven that she really loves, so that is worth it I would say.

Thanks again for the replys

Ken

SloopJohnB@mac.com

My wife gets about 17.5-18.5 on her 2K4.2A6 as well.

Good advice on the intake manifold variable intake manifold runner flaps.