yea in the summer, i was getting 380-400 miles to the tank here in Vermont.. and this winter it has dropped to 300-330 with this badasssss cold weather.. definatley has to be the winter

 

ok i know i have an a6, but i have the same 2.8. im getting HORRIBLE gas mileage. i drive mostly city, and get 13 mpg if i drive like an old man, meaning never letting it go above 2000 rpms. ive changed the air filter, oil and filter (5w40 mobile 1 synthetic), cleaned the MAF sensor (it was clean to begin with but now its spotless), and changed the plugs to bosch platinum 4's. basically a full tune up. now one thing i notice, when idling, i have a slight random rpm bounce. and its not much maybe itll bounce a total distance of 2-250 rpms n go right back up, and a few seconds later itll do it again. but never bad enough to almost stall the car, not even close. any ideas? no lights on the dash either.

 

I wouldn't be too worried. I get about 220 a tank in the city and 275 all highway. This is with bad o2 sensors, dirty cone filter, and a lead foot. You'll most likely get even worse gas mileage with the cone filter. If your car is over 100k I'd look into changing the rear o2 sensors soon.

 

I get about 400 on the highway

 

trey25, I was just looking into getting a cone filter for my 2.8 because i thought they give you better gas mileage? Now you say they give you worse mileage, why is that? Also, which cone filter do you have?

 

I have a k&n cone filter. The throttle response improved due to better engine breathing. But the downside to that was about a 2mpg decrease. Heat soak in the summer doesn't help either. It really didnt bother me cause the sound alone was worth it. If you do go with the cone filter make sure to periodically clean and re-oil the filter or the maf reading will be off, which only leads to worse mpg. I've talked to a couple audi techs and they both agree the stock airbox is best cause the maf reading is very sensitive. It's your choice really. Again, to improve mpg do a full tune up and change rear o2 sensors, they're notoriously flimsy over 100k.

 

thanks, maybe ill think about it some more or wait until the spring rolls around for the K&N filter. As far as the O2 sensors go, should I replace the front ones too with the back ones? Where do you get them, how much are they, and how do you replace them?

Also, are there any other products out there specifically for audis that will increase gas mileage?

thanks again

 

I'm sorry, it's the precat sensors that affect fuel trim. The postcat sensors monitor catalyst performance. Not quiet sure if their readings influence fuel trim also. Oxygen sensors are expensive on these cars. The cheapest I could find was at www.autohausaz.com

 

^^^^^anyone have anything on my issue? im averaging 10 mpg

 

i don't have any solution to your problem, but i get the same exact dips in my rpm randomly. sometimes my car will straight up idle at around 400 rpm which is only slightly off from where it should be.

the other problem is that your lugging around a lot more weight than us a4 guys which would mean that your engine is working harder than our 2.8s to get up to speed. apart from that im straight out of ideas.