very poor MPG--need help!!!

[bullomar]

Hi guys,

I drive 2006 A4, 2.0 TFSI Quattro with everything stock.

in last 6 months or more my MPG are very poor.
In city I get only from 10-13mpg and that is the best I could do in last 5-6 months.
On highway, I can get some 18-20 mpg only.
I am reading all the time that you guys can get in city 25-26 or more MPG on your audis and this sounds strange for me!
I just made a service on 65.000 miles and have no problems accept the poor MPG.
In the past, I changed my:

- PCV (twice)
- coil packs OEM
- spark plugs OEM
- I had K&N filter but now it is stock again
- changed cam follower (looks good now)
-changed stock DV with the new one (twice so far, just to be sure)

I am using Castrol Edge 5w30 or Mobil1 0w40 from time to time...

What should I look for?
I dont think there is some air leak...
could it be related to some sensors?

thank you all

Omar

[jimrobbington]

Fouled O2 sensors would cause a CEL, so it's prob. not that. Maybe a really bad fuel filter? That's bad. I get about 19-22 city and that's about as bad as it gets for me. You might as well have a v10 with milage that bad. Maybe a really dirty air filter?

[jimrobbington]

worst milage i got was 6 mpg on the auto x track

[EuroA4]

Check your plug condition again...they could be fouled or in other poor condition.
Also a dirty MAF could also causing the issue since you did have the K&N.
Sometimes it gets oil on it and starts to read wrong.
Try some CFC brand MAF cleaner.

If you are still not getting better mpg...replace the O2 sensor.

Boost gauge would be good too to help you diagnose boost/vacuum leaks!

[crew]

I can't say it'll be the definitive problem, but make sure your tires are up to pressure and consistent.

I agree with Jim, check the air filter and intakes to see if there's a squirrel family in there.

[teamdaraptor]

I've ran Lucas brand injector cleaner and upper head cleaner through the car every fuel fill up and holy crap... my jeep's MPG went up QUIIIIITE a bit. Im talkin I normally get 12-13 TOPS and I drive like a granny... I was hitting high 16's mid 17's.. Not to mention the pedal feels a bit touchier.. so the throttle response seemed to be a bit better. Put it in the Audi as well, and she ran amazingly. Worth a shot... They come in big gallon jugs, smaller like 100oz bottles, and a small one use sorta thing. Since you already changed your plugs and packs, not sure what else to check. Do like the others said and check that MAF and air filter. Those can cause some problems for ya.

[vannyhuj]

Agree with all above. Check tire pressure for sure, but it shouldn't cause that big of a jump. I would do the following in order:

1) clean/check your snow screen filter (pre-air filter screen)
2) clean your MAF
3) check your plugs again (condition, gap, torqued properly)
4) maybe replace O2 sensors . . . but this should cause a CEL so not sure there.

If you are higher mileage you probably want to change your fuel filter as well, but I don't think it would cause this sort of jump either.

[bullomar]

Fouled O2 sensors would cause a CEL, so it's prob. not that. Maybe a really bad fuel filter? That's bad. I get about 19-22 city and that's about as bad as it gets for me. You might as well have a v10 with milage that bad. Maybe a really dirty air filter?

Hi jimrobbington

as I have said, I just did the service and I have changed air filter, clima filter as well as oil filter.
My fuel filter is changed maybe few weeks ago.
I replaced my K&N filte with the stock one and I have cleaned my MAF with the contact cleaner...

:)

[bullomar]

Agree with all above. Check tire pressure for sure, but it shouldn't cause that big of a jump. I would do the following in order:

1) clean/check your snow screen filter (pre-air filter screen)
2) clean your MAF
3) check your plugs again (condition, gap, torqued properly)
4) maybe replace O2 sensors . . . but this should cause a CEL so not sure there.

If you are higher mileage you probably want to change your fuel filter as well, but I don't think it would cause this sort of jump either.

Hi vannyhuj

I throw my snow screen filter one year ago after I have installed my K&N filter.
Since I made a full ervice and I changed my air filter, oil, oil filter, clima filter etc, I have also cleaned my MAF and now I use OEM air filter.

One important thing which I did not say is I have installed down pipe so I get my o2 sensor CEL code.

Could this be the problem?
Should I put the spaces for post cat o2 sensor?
Should I change o2 sensors and if yes, do you guys think I should change both of them or only the post cat one?

Thanks

[BigRob]

Im just wondering how many miles you guys get overall on a tank of gas? When I got my 2007 A4 quattro 3 months ago the first fill up after getting it from the dealer I reset the trip meter and got around 420 miles. Now I barely get 350 and I use 93 octane. Does this sound about right? I dont drive like a maniac and most of its highway miles

[Swerve]

One important thing which I did not say is I have installed down pipe so I get my o2 sensor CEL code.


Thanks

This is most likely your problem, your air/feul ratio is messed up, you are running really rich, hence the bad gas mileage.

[makav3li]

Im just wondering how many miles you guys get overall on a tank of gas? When I got my 2007 A4 quattro 3 months ago the first fill up after getting it from the dealer I reset the trip meter and got around 420 miles. Now I barely get 350 and I use 93 octane. Does this sound about right? I dont drive like a maniac and most of its highway miles

Fill up your tires...i was blown away of the increase of gas mileage i got just from keeping the tires up to par, it went from 350 per tank to a solid 400.

This is most likely your problem, your air/feul ratio is messed up, you are running really rich, hence the bad gas mileage.

I'm guessing the downpipe included a test pipe (a pipe that replaces the catalytic converter) and that would not cause bad gas mileage. Its the forward o2 sensor that would affect the a/f mixture but the aft one only monitors if the cat is doing its emissions job.

Your intake flap motor usually causes a code but i know it deff affects your gas mileage. I'd look more into your flap motor, maybe theres a way to motor to see how far open it is when idle using a vag-com.

[bullomar]

Fill up your tires...i was blown away of the increase of gas mileage i got just from keeping the tires up to par, it went from 350 per tank to a solid 400.



I'm guessing the downpipe included a test pipe (a pipe that replaces the catalytic converter) and that would not cause bad gas mileage. Its the forward o2 sensor that would affect the a/f mixture but the aft one only monitors if the cat is doing its emissions job.

Your intake flap motor usually causes a code but i know it deff affects your gas mileage. I'd look more into your flap motor, maybe theres a way to motor to see how far open it is when idle using a vag-com.

hi makav3li,

I ment to say that I have installed only test pipe without a down pipe.
So my cat is only replaced with the test pipe and I do get o2 -lambda CEL codes.

Also, you are wright about flap motor since I am getting this code all the time.
I just did not want to believe, it could effect my MPG so I did not check for it since now.
It seems, I will need to check my flap motor and to install some spacer between o2 sensor and test pipe and avoid further o2 codes!?

Question, do I need to change my flap motor? What goes wrong with it? Does it only get dirty from gases, carbon deposits etc so I could clean it and fix the problem or I will need to change my flap with the new one?

Thanks again

[makav3li]

hi makav3li,

I ment to say that I have installed only test pipe without a down pipe.
So my cat is only replaced with the test pipe and I do get o2 -lambda CEL codes.

Also, you are wright about flap motor since I am getting this code all the time.
I just did not want to believe, it could effect my MPG so I did not check for it since now.
It seems, I will need to check my flap motor and to install some spacer between o2 sensor and test pipe and avoid further o2 codes!?

Question, do I need to change my flap motor? What goes wrong with it? Does it only get dirty from gases, carbon deposits etc so I could clean it and fix the problem or I will need to change my flap with the new one?

Thanks again

You can try to install a spacer on your o2 sensor but 4/5 times it doesn't help, still causes the code. The best way to get rid of it is to get a stage 2 tune from either apr/giac/revo/etc... and it will completely delete that code from your ecu. But your problem does not lie with that code, you can drive all day with that code and it will not effect your gas mileage or anything else on the car, so you can ignore it if youd like. But you might as well get a stage 2 tune cuz not only does it get rid of the code but it'll bump up your HP/TQ about 50 in each.

I personally have not dealt with the flap motor but I've read a little about it here and there on the forum. But here is the DIY I've found for it.

http://www.audizine.com/forum/showth...flap+motor+diy

From what I understand, the flap motor effects your air/fuel ratio and alot of times it'll get stuck in the full open position causing you to run rich. Other than that, I'm not very knowledable when it comes to this problem. If you don't feel confident in doing it yourself, I'd say bring it to an independent shop and I'm sure they will be familar with the problem seeing as how its a pretty common b7 issue, just make sure they are familar with audi's and know whats goin on. Or just suck it up and bring it to the dealer and have them do it correctly but I'm sure it'll be noticable more expensive than the indy shop.

Hope I helped.

[bullomar]

You can try to install a spacer on your o2 sensor but 4/5 times it doesn't help, still causes the code. The best way to get rid of it is to get a stage 2 tune from either apr/giac/revo/etc... and it will completely delete that code from your ecu. But your problem does not lie with that code, you can drive all day with that code and it will not effect your gas mileage or anything else on the car, so you can ignore it if youd like. But you might as well get a stage 2 tune cuz not only does it get rid of the code but it'll bump up your HP/TQ about 50 in each.

I personally have not dealt with the flap motor but I've read a little about it here and there on the forum. But here is the DIY I've found for it.

http://www.audizine.com/forum/showth...flap+motor+diy

From what I understand, the flap motor effects your air/fuel ratio and alot of times it'll get stuck in the full open position causing you to run rich. Other than that, I'm not very knowledable when it comes to this problem. If you don't feel confident in doing it yourself, I'd say bring it to an independent shop and I'm sure they will be familar with the problem seeing as how its a pretty common b7 issue, just make sure they are familar with audi's and know whats goin on. Or just suck it up and bring it to the dealer and have them do it correctly but I'm sure it'll be noticable more expensive than the indy shop.

Hope I helped.

Hi again makav3li,

thank you for the info about the o2 sensor as well for other...

I will try to look my flap motor and to see what is wrong.

Thanks for all

[01kwt2000]

Does it start hard in the morning when it's cold could be corbon deposit on the valve same thing happened to my friend with a a6 3.2 dealer changed everything and was still doing it the performed the bg cleaning once it helped so they took it apart and valves were filled with crapp deposit did some manual cleaning put it together and now he's getting consistent 26 hwy
I know it's an a4 but the 2.0 and 3.2 share this stupid problem

[B72.0T]

Mozda ti je carbon building problem...

[makav3li]

carbon buildup sucks really bad but is more prevalent in the 3.2's rather than the 2.0's. Some things you can try to prevent CB is to get a bsh catch can, dont take small trips often, make sure it fully warms up before shutting off. And deff do some spirited driving everyday, deff bring it up to redline around once a day when the car is fully warmed up. Thatll hopefully burn off the carbon in the engine.

[mr shickadance]

you can get one of those tornado things and put it in your inlet hose....haha

[A42S4]

remove led foot

[Coderedpl]

I think I have to do this as my mpg sucks aswell
planning these this weekend..
Carbonio filter clean
Maf cleaner
Injector and head cleaner

Later
Fuel filter

What should tire pressure be? Im guessing around 35psi? I think my tires said 40max

[A 4 Awesome]

I run 36PSI on my stock 17's. per the tire guy.

[bullomar]

Mozda ti je carbon building problem...

hvala...provjerit cu :)

[bullomar]

carbon buildup sucks really bad but is more prevalent in the 3.2's rather than the 2.0's. Some things you can try to prevent CB is to get a bsh catch can, dont take small trips often, make sure it fully warms up before shutting off. And deff do some spirited driving everyday, deff bring it up to redline around once a day when the car is fully warmed up. Thatll hopefully burn off the carbon in the engine.

I will try to check my flap motor first in net few days and if that dont help me, I will check for carbon build ups...

keep you informed...

:)

[makav3li]

please do :) im always curious to see outcomes so if something like this happens to me, i know where to look and can say fuck u dealership and your inflated prices and gay fuckin fuck fucks

yea...fuck fucks, yall dont even know

[Coderedpl]

please do :) im always curious to see outcomes so if something like this happens to me, i know where to look and can say fuck u dealership and your inflated prices and gay fuckin fuck fucks

yea...fuck fucks, yall dont even know

We do, we do;
http://www.youtube.com/watch?v=26UA578yQ5g

[01kwt2000]

Did u try cleaning the throttle body I just did min at 60k it was filthy took me 15 min completely with realigning it millage went up a bit but it idles and runs better just a thought good luck

[Coderedpl]

Did u try cleaning the throttle body I just did min at 60k it was filthy took me 15 min completely with realigning it millage went up a bit but it idles and runs better just a thought good luck

How'd you go about doing that?

[CoDRoX]

Are you using the right oil? 10W-Khhhhhhhhh is the correct one.

[Trile]

hvala...provjerit cu :)

sigurno ti nije to... Moj audi je preshao 140.000 km, i kad ja nemam takvih problema posle nasheg losheg goriva, sumnjam da je to uzrok.I da, i ja imam test pipe... kroz grad mi trosi oko 12-13 litara normalne voznje.

Sorry for the non-english conversation everybody ;)

[vwnobby]

How'd you go about doing that?

I just cleaned my MAF sensor and throttle body today. For the throttle body, I disconnected the two electrical connectors, then I disconnected the hose coming from the second intercooler to the throttle body. After that all you need is a T30 torx (a long one is best) and remove the 4 screws holding it in. I then used throttle body cleaner, a shop towel and some cotton swabs (Q-Tips) to clean up as much as I could. After I put it all back together I did a throttle body realignment using VAG-COM (engine > basic settings > block 060 > turn on basic settings and wait for last field to read OK) the other option is to turn on the ignition (don't start car) press the gas pedal all the way down for 3 seconds, turn the car off, let the gas pedal up and wait 2 minutes - then start the car.
Hope this helps.

[Coderedpl]

I just cleaned my MAF sensor and throttle body today. For the throttle body, I disconnected the two electrical connectors, then I disconnected the hose coming from the second intercooler to the throttle body. After that all you need is a T30 torx (a long one is best) and remove the 4 screws holding it in. I then used throttle body cleaner, a shop towel and some cotton swabs (Q-Tips) to clean up as much as I could. After I put it all back together I did a throttle body realignment using VAG-COM (engine > basic settings > block 060 > turn on basic settings and wait for last field to read OK) the other option is to turn on the ignition (don't start car) press the gas pedal all the way down for 3 seconds, turn the car off, let the gas pedal up and wait 2 minutes - then start the car.
Hope this helps.

Did you wait long to let it dry up or no? How long did it all take you?

Was planning to do this before i go on a drive but dont want it to waste too much of my time and want to know if i will have enough for it to dry off

[vwnobby]

Did you wait long to let it dry up or no? How long did it all take you?

Was planning to do this before i go on a drive but dont want it to waste too much of my time and want to know if i will have enough for it to dry off

Yes, I waited, but to be honest that stuff dries/evaporates in a matter of 10 to 20 seconds. I blew it out carefully with the compressor, just to make sure.
To do the MAF & TB took me about 15-20 minutes. While I cleaned the TB, I let the MAF sit upright just to make sure if cleaner was left it would drip down, away from the sensor.

[01kwt2000]

That's what I did but to sinc my throtle body all I did is turn the key on till all lights are on then wait 20 sec iff its quiet and u have ur hood open you'll hear it sincing then stop but I'll give the pedal to the floor method to see if there's a difference

[Tanner]

The intake manifold flap is to help improve the fuel burn. It's partially closed at idle and believe it might be mostly open when you're maintaining constant speed and it's definitely opened under full throttle. I really doubt that the intake manifold flap stuck in the open position will cause a huge negative impact on mileage. Mine was stuck open (default position when the intake manifold flap controller fails) and my mileage didn't change.

[Coderedpl]

My mileage drastically changed when my N80 valve went out.

[beantown]

^^ I think mine just did. My MIL just came on and after scanning I'm getting a P0441 code.

[DirtyBeemerGS]

This thread is a month old, but I figred'd better to chime then start a new one. Right?

I just bought my 08 B7 2.0 quattro Auto 2 months ago coming from a 08 Nismo 350Z. On paper the gas milege seemed better than the Z so its was a selling point for me. Since I got the A4 the gas mileage has been significantly less than what I figured. Of course I would say too that 85% of my driving per tank is city. I just live and work in one of those areas where you dont need get on the highway that much, unless you need to go really far.

As I came home tonight the fuel light JUST came on. The trip odo said 268 miles. I hit reset on the last fill up. 93 oct too. The dash ,on average, displays anywhere from 21 to 24mpg.

I changed the air filter and cleaned out the snow filter right after I got the A4. Which only had 12k miles on it when I got it. I haven done much else to it yet, maintenance wise.

So I was just wondering, if that seems like an appropriate number considering all the factors? Or is that pretty bad?

Thanks

[Tanner]

Turbocharged engine + stop and go traffic = not great mileage

If you can some how minimize on hitting the red lights, that'll probably be the single biggest thing you can do to improve mileage.

[DirtyBeemerGS]

Thanks for the input. I figured it was that 85% of my driving is city type driving. I also thought it was my foot trying to poke the tranny back to life every once it a while. Its seems the shift logic always wants to get the tranny into 5th or 6th ASAP. I know going to and from work, I have to give it gas to nudge the tranny to drop a few to get up a hill. Otherwise it seems to want to stay in 5th or what have you.

Maybe im just too used to driving mt's the past 11 years.