Gas Mileage

**Phresh S4** · 03-17-2010 06:35 AM

What kind of gas mileage do you guys get? MY car is stock btw and I got 240 Miles on a full tank of gas. I dont know if this is normal or is my car wasting more gas than it should?

**stamps** · 03-17-2010 06:38 AM

no good, durring my stage 3 break in I was getting over 400 to the tank, but that is keeping under 3k all day. either way you need to change something, most likely driving habits but could be o2's, egts... any codes?

**Phresh S4** · 03-17-2010 06:40 AM

No codes, and the o2's are all brand new. I figured something wasn't right. The car seems to shake a little when its idling so i was thinking that changing the spark plugs would help out a little.

**KNaudi** · 03-17-2010 06:40 AM

there seems to be a new gas mileage thread every week or so, search for these.

240 for a tank, especially stock, is terrible. I get better than that 80% city driving and I'm stage 3. You should check for codes relating to EGT and 02 sensors.... that's just a shot in the dark, but those items have huge impacts on mileage.

Oh and you should change out the fuel filter if you haven't done so yet.

edit: you beat me to the codes bit. But yea, plugs and filters might help significantly.

**S4evr** · 03-17-2010 06:41 AM

i get 200 on city/highway mix stage 3. But my EGT is dead so I'm probably just DUMPING fuel

**Phresh S4** · 03-17-2010 06:42 AM

Ill do that asap

**98a4** · 03-17-2010 06:45 AM

~20mpg highway at 80mph cruise. I'm in the middle of tracking mileage on my current fillup. No current codes related to EGT or Primary 02's

**Phresh S4** · 03-17-2010 06:47 AM

im gonna change my oil, plugs, fuel filter and put that lucas system cleaner in my tank and see if that helps me at all.

**Dimcorner** · 03-17-2010 08:16 AM

I'm with K04 on Stg2 ECU, stock exhaust and IC's.
I'm getting 22mpg with 80% city driving (about 280-300 miles until the light comes up).
I have an intermittent O2 code as well.
All HWY doing 70-75 I get about 26-28mpg.

**TWiST** · 03-17-2010 12:58 PM

While were on the subject any fuel filter change DIY articles I found one on the world that used to have pics but does not anymore

**Dimcorner** · 03-17-2010 01:05 PM

It's REALLY easy to do.
The part the pics don't show you is that the line in the back of the filter is a PITA to get to. My problem was when I was putting it back together I had to rotate the filter just a hair and it loosened up the top feed line. You could smell small amount of fuel vapor after a 2 days. I had to drop the tank a bit again and reach in there to tighten it and it was all good.

That and I didn't tighten down the fuel filter clamp super hard.

**TWiST** · 03-17-2010 01:17 PM

I have 196,000 on the odom and I have dont think it has ever been changed lol, thats why im sure I need to, and my EGTs are shot and I get awful mileage

**YnotS4** · 03-17-2010 09:01 PM

Check your thermostate position sensor also switch to the green one, this will also cause the car to run rich

**flyingfish2626** · 03-18-2010 06:59 PM

I just started running APR 100 octane program with my KO3's and I am only getting 200 miles to a tank running meth. Just replaced my EGT's and have never thrown a O2 code ever. Any ideas besides getting a custom chip from Vast?

**jukesandz** · 03-18-2010 07:51 PM

Stage 2 isn't bad. Around town, I average around 19 mpg and on the highway around 25 mpg @ 75 mph.

**Raacerx** · 03-18-2010 10:15 PM

i imagine its been said, but plugs. #1 place to look for lack in mileage if u havent replace them in awhile. go for the sidefires. I get between 250 and 390 miles per tank, all dependent on how I am driving, and where I am driving. I can average 26mpg on the highway when I cruise 70mph, 225/45R17 tires. I also baby it in town when the turbos are cold, shifting below 2k usually. 300+ is my normal. 350 with highway. ~400 if ALL highway. (225-250 with hardcore driving), and around 165 miles @ the track

works out to between 20-22mpg total average, since I do primarily city driving.

**BEE5S4** · 03-19-2010 05:55 AM

My avant has never seen better than 250 mi to the tank.

**The_Jerbel** · 03-19-2010 01:15 PM

The biggest factor in your fuel mileage is how heavy your foot is.

**Kruat** · 03-19-2010 01:57 PM

I routinely get over 300 a tank. But not by much. I think I average around 310-320. But I drive 75% freeway, about 65mph, and around 50 miles round trip. My car is nearly stock, but I do have heavy ass 19's. I suspect once I put my 17's back on this weekend, my mileage will go back up to around 350 a tank.

**lbs4** · 03-19-2010 02:12 PM

it seems like my milage is horrible too and i drive my car really easy since most of my driving is only 2 miles to and from work and if i do any running around while at work i dont go over 5 miles so the car doesnt warm up all the way. i dont have my 2 rear o2s anymore so i think it could be that. also i want to do my plugs, what do you all suggest?

**KNaudi** · 03-19-2010 02:19 PM

Originally Posted by lbs4

it seems like my milage is horrible too and i drive my car really easy since most of my driving is only 2 miles to and from work and if i do any running around while at work i dont go over 5 miles so the car doesnt warm up all the way. i dont have my 2 rear o2s anymore so i think it could be that. also i want to do my plugs, what do you all suggest?

car runs rich-er when not warmed up.

**Coors** · 03-19-2010 03:22 PM

Originally Posted by Raacerx

i imagine its been said, but plugs. #1 place to look for lack in mileage if u havent replace them in awhile. go for the sidefires. I get between 250 and 390 miles per tank, all dependent on how I am driving, and where I am driving. I can average 26mpg on the highway when I cruise 70mph, 225/45R17 tires. I also baby it in town when the turbos are cold, shifting below 2k usually. 300+ is my normal. 350 with highway. ~400 if ALL highway. (225-250 with hardcore driving), and around 165 miles @ the track

works out to between 20-22mpg total average, since I do primarily city driving.

I'm about the same above in a heavier A6 6spd. ko4's stage 3minus. 400+ highway to empty. Avg about 26mpg's highway. No cel's. stock cats.

**CONTROL ONE** · 03-19-2010 03:28 PM

Originally Posted by lbs4

it seems like my milage is horrible too and i drive my car really easy since most of my driving is only 2 miles to and from work and if i do any running around while at work i dont go over 5 miles so the car doesnt warm up all the way. i dont have my 2 rear o2s anymore so i think it could be that. also i want to do my plugs, what do you all suggest?

Your rear o2s do not control your fuel consumption, they are only there to check to see if the cat is working properly.

You answered your own question with the short, cold trips.

**lbs4** · 03-19-2010 05:20 PM

i wasnt aware of that, thats good to know. i read on another thread something about awe tuning stage 3 kits getting bad mileage because of something to do with the rear o2s, but i may have misread it, thats why i thaught something of my rear 02's causeing mty bad gas mileage.

**happy2B5** · 03-20-2010 09:41 AM

I don't see much better than OP either. I was really disappointed on a recent road trip to Park City from Cali. Then again most of the cruising speeds were around 80 or so with skis up top. Climbing slight grade most of the way there. Left with a full tank and made 3 more stops on a 900 mile trip (did not even avg 20 mpg). I need to look at replacing plugs, fuel filter etc...no codes for me - STG 2.

**blackjak** · 12-04-2010 09:19 PM

This thread is a bit old, but rather then creating a new one I thought I just bump her up, I am averaging the same as OP around 240, which is honestly ****in terrible my 02 Infiniti QX4 got atleast 275. FFS. I am replacing fuel filter tom, hopefully that helps maybe Il put in some injector cleaner and replace the spark plugs, if no increase I am selling the Sex4 for the lowest bid I only accept pesos. I am to lazy to search can someone point thine good fellow in a prosperous direction. TIA ye filthy dogs

**Scotty@Advanced** · 12-05-2010 08:12 AM

Originally Posted by blackjak

This thread is a bit old, but rather then creating a new one I thought I just bump her up, I am averaging the same as OP around 240, which is honestly ****in terrible my 02 Infiniti QX4 got atleast 275. FFS. I am replacing fuel filter tom, hopefully that helps maybe Il put in some injector cleaner and replace the spark plugs, if no increase I am selling the Sex4 for the lowest bid I only accept pesos. I am to lazy to search can someone point thine good fellow in a prosperous direction. TIA ye filthy dogs

Some people are comparing apples to oranges, fuel tank sizes differ and more fuel you have on board the farther you can go per tank. The QX4 has a 21 gallon tank, the S4 16.4.

**P0234** · 12-05-2010 08:24 AM

Originally Posted by blackjak

I am replacing fuel filter tom, hopefully that helps maybe Il put in some injector cleaner and replace the spark plugs,

A plugged fuel filter can cause a bad running car, but decrease mileage, don't think so. If a car runs fine otherwise, no way in hell its the fuel filter.

**alexverve** · 12-05-2010 08:29 AM

the best i've seen is ~320 miles on a tank. all highway. usually, 240-250 mix...

**DiscoPotato** · 12-05-2010 08:46 AM

I did a 1500 mile rally and we got 24 mpg (a lot of highway) but we also did not do close to the speed limit

**Dorny1** · 12-05-2010 08:47 AM

ive seen 380 twice since i had the car but i'm usually 340mi but i'm nice to my car...alot

**Phresh S4** · 12-05-2010 08:56 AM

Originally Posted by Scotty@Advanced

Some people are comparing apples to oranges, fuel tank sizes differ and more fuel you have on board the farther you can go per tank. The QX4 has a 21 gallon tank, the S4 16.4.

16.4?? Wow when my car is totally empty and I let if fill up, it always stops at about 14.4 gallons

**YnotS4** · 12-05-2010 08:59 AM

I average 22.4 city highway combined

**bigdo26** · 12-05-2010 09:15 AM

best ever is 23.2, average between 20-22.

Worst is around 8. That was at the track though ;)

**Dimcorner** · 12-05-2010 09:15 AM

Originally Posted by Phresh S4

16.4?? Wow when my car is totally empty and I let if fill up, it always stops at about 14.4 gallons

same here. I'm not willing to try and test out the 16 gal theory thou :)
Most I have filled out is 14.940 (I track ALL my fill ups)

**Voodoo08** · 12-05-2010 09:29 AM

Im averaging between 24-25 mpg. Mix of spirited and conservative

**ski&drive** · 12-05-2010 11:59 AM

i had intermittent primary o2 codes and was getting around 18 highway with a ski rack on.

Just went up to montreal for the night and got 24 with the rack on averaging about 70mph

Without the rack i gain like 4mpg

**70 eliminator** · 12-05-2010 12:44 PM

i hate the fuel tank size on the s4 my 91 20v gets 27 to 29 mpg highway with the 2..2 inline and its not uncommon toi get 440 on the tank but it is like 22 gallons. i wish the s4 had bigger tank...

my tiptronic avant gets 23 to 24 on highway and i am babying it because ko3;s are allmost dead.... and i live at altitude so lots of hills etc. work is 40miles away and 2k elevation loss