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Audihrr
04-21-2007, 07:11 PM
[headbang] as expensive as gas is today I need to figure this issue out fast. I have a 2000 1.8t B5 A4 with auto tip. APR software and have replaced maf, new ngk plugs, and am getting right around only 19MPG.

What the fuck is going on? is it my cat clogged? It also feels very restricted or like it is bogging down.
Had the codes read yesterday and there were intermittent codes for bank 2 sensor 1 O2, and intermittent running lean codes stored. They were cleared and....

Help
Thanks[headbang]

mike-2ptzero
04-21-2007, 07:30 PM
Do you mean Bank 1 sensor 1? Because the 1.8t should not throw a code for bank 2.


Problem is that your precat 02 sensor is going bad, making the ecu think you are running leaner then it really is and this is why your gas mileage is gettting worse. Time to buy a new 02 sensor.

Audihrr
04-21-2007, 08:40 PM
Just had bank 1 sensor 1 replaced less than 2000 miles ago. It was throwing an intermittent code as well and I couldn't have the ecu flashed until it had been taken care of. The code just cleared was bank 2 sensor 1.
If it is running lean would it occasionally make it so when driving you smell that nasty sulfur type smell for a minute or two or is that if it is running rich?

Also are there any other related drivability issues related to O2 sensor troubles?
Thanks

Militant-Grunt
04-21-2007, 09:32 PM
I get about 20-21 combined highway/ city when driving semi economically. What do people get combined usually?

Audihrr
04-21-2007, 09:51 PM
I get responses like "19mpg with a 1.8?" I have been hearing around the 24-28 as high as 30 mpg range. 19 is way low though, right?
Also the sulfur smell. Yuck

Tiluleshpingen
04-21-2007, 09:58 PM
omg same problems as me.. on 6 gallons i got about 93miles

mike-2ptzero
04-21-2007, 10:17 PM
Just had bank 1 sensor 1 replaced less than 2000 miles ago. It was throwing an intermittent code as well and I couldn't have the ecu flashed until it had been taken care of. The code just cleared was bank 2 sensor 1.
If it is running lean would it occasionally make it so when driving you smell that nasty sulfur type smell for a minute or two or is that if it is running rich?

Also are there any other related drivability issues related to O2 sensor troubles?
Thanks

Bank 2 sensor 1 is the precat 02 sensor for a V6/V8, which you dont have. Might be easier if you posted up the DTC #. You could have a issue with the plug or wire harness for your precat 02 sensor.

ImArider
04-23-2007, 06:35 PM
i have a very similar problem. i drive a 2001 2.8 and im getting only 15mpg. i usually average around 21 based on the dash computer. plus i already no one of my sensors is bad because my mechanic said so. even more importantly i smell that sulfur smell which i have been thinking is my clutch. im about to have my clutch replaced at then end of the week. so i need to no if that smell could be related to the sensor instead of the clutch. plus is that sensor whats sucking up all my gas? im desperite for good info car is taking all my cash and sanity.

AudiA4_20T
04-23-2007, 07:59 PM
o2 sensors, air filters, plugs, and MAF will all do this so check there

also a nice seafoam treatment might clean out any sludge thats bogging down your motor and free up a few MPG

brlukosk
04-23-2007, 08:51 PM
Dash computer is messed up.

It will drop from 210 to 195 in seconds..

I can get 23-25mpg cruising on the highway for 60-70 miles at 80mpg average..

In town, driving to work, running to the store, getting groceries I get about 18.8 to 19.0, however I live in the city so I am never driving without stoping and re-accelerating to 40 for 2 or more min.

Monchichi8
05-26-2007, 12:04 PM
I am getting 16 mpg on my 2001 1.8 qmt!! it sucks.!!!... and thats around town, driving easy. So i guess what Mike is saying is change the O2 sensor, right?? I used to get 300- 350 miles out of a tank. F@%K!

Ewok_Fetus
05-26-2007, 12:20 PM
Hahaha, 19mpg here is what I usually get... Though this last tank I did manage to get about 27 by taking it easy! Never let it get into the boost at all and shift soon, but not too soon!!

onemoremile
05-26-2007, 01:00 PM
I get 25-28 in town and 30-38 on the open road. 20-25 in Detroit's gridlock.

sean1.8t
05-26-2007, 01:03 PM
I get 25-28 in town and 30-38 on the open road. 20-25 in Detroit's gridlock.

are you going by what the DIS screen tells you. or are you actually calculating it yourself at fillup?

onemoremile
05-26-2007, 01:08 PM
Both. I flip through the screens and reset them all with each fillup. Then punch the numbers into my phone to see how accurate the screen is. It is usually within a couple percent and never more than 10% off. If it says 30 I'm actually getting between 28 and 32. Average speed for a tank is usually about 22 mph in town. For a round trip to my mom's house (65 miles each way, mostly highway, stops through several towns) the screen showed 42.5 but it calculated at just over 38.

30-40 mph is the sweet spot for the best possible fuel economy. That is because it is right under where aerodynamics start slowing things back down. The rapid starts and playing in boost is what kills economy. If I drive crazy I can average in the teens but there is no point to that. If I drive with traffic with an occasional WOT I get the great numbers posted above.