whitacre

So im assuming my cars' previous owners took out the airfilter because they saw somewhere or heard from someone that it improves gas mileage. I would have to concur considering i used to get 23-26 crusing down the highway...right after putting my airfilter in, letting it run for a couple minutes, then driving off, the sputtering slowly stopped, but the mileage for gas just was a shocking number. from 25avg going about 65 on a country road, to 14-16.5, even letting off the accelerator to see if it would go up a little more, which it did, but not much. This car is just so much fun!

Adam Mowafy

How long has it been with no air filter?...........

audiqv8

If you're only getting 14-16.5 mpg and the O2 sensor have over 60,000 miles on it, then it is time to change the O2 sensor. Also did you ever find your fuel leak?? This will also cause low gas mileage.

Make sure you're sitting down when they quote you the price. If you thought $65.00 was high for a fuel hose then you're going to be sticker shock for the O2 sensor.

If you do the work yourself then you can buy a generic Bosch Ford 5.0L four wires (original have only three wires) and ground the fourth wire.

You should also pull the fuse for the ECU. The ECU uses an adaptive learning to determine how you drive and how the engine perform. If you have been driving without an air filter then it have adapted the fuel/air mixture to this condition.

Dikiz_LT

oh scary story...the car without air filter :/
i think that the engine can be a litle worn :/
i can imagine how much sand and other stuff he have eaten :/

for poor gas mileage try to check o2 sensor,ecu temp. sensor, mayby your car runs too rich ),or cracked upper turbo hose.

whitacre

Well no telling how long it has been without an airfilter...I know it was not with one for the time i have owned it (3 months). I will check to O2 sensor, but nothing really shocks me in price when im talking Audi. Whether i can afford it or not is another story. Also, where is the ECU at? i have searched and looked around in the car, but cant find anything?

Thanks guys!

Quattrotrac

The ECU is located underneath the dash (driver's side). To access it, you need to remove driver's side knee bolster pad located below the steering wheel and column. Once removed you will see two ECUs. The main (the one you're looking for) ECU is the upper of the two, and labelled Motronic. The other ECU is for the automatic transmission. Don't try and separate the two while they're underneath there, remove them both and then separate them because they are bolted to the same plate.

audiqv8

<center><img src="http://pictureposter.audiworld.com/36396/audiv8-mod.jpg"></center><p>The ECU is item number 6. Fuse panel is number 2 located behind the passenger side kick panel.

whitacre

Wow, im actually comfortable with my car today. I redid the ECU as you guys mentioned, and ever since i had that air filter in, i dont smell any more gas, and dont see any dripping on the car underneath. Also, after doing that ecu thing, my gas mileage is back up a considerable amount, AND i dont know if this has to do with anything, but it shifts different now...almost smoother. Its quite awesome.