Bad Gas Mileage [Merged 9-6]

[99GST]

I am still getting some pretty bad gas mileage.

I am only getting about 19.7 mpg with mostly city driving shifting at 4k.
I have already replaced my front O2 sensor and am looking to replace the fuel filter.

I have a 99gst with about 55k miles on it. Should my fuel filter already be bad?

What else should I check or change? I have NKG plugs and Accel wires are on the way.

Thanks,
Nathan

 

[c4uldr0n]

I have a '92 TSI AWD w/ 550CC + 16G... I've had as low as 145 miles per tank (11mpg) when I'm really on it, and I've had as good as 290 miles per tank (22mpg) when I'm on a 70mph road trip. Not exactly economy, but it is fun as hell.

 

[DSMnOOb00]

WoW is the GSX really that much of a gas hog? my old RS and GST got about the same miles pre gallon, but with the gsx its like i can almost see the needle move *altho i do punch it when ever i get a chance =0) * oh well, i already changed my oil (high mileage), but i guess i should check the 02 senser, what should i look for? thats the one under the turbo going out the the cat right?

 

[elfroggo]

Why don't you try measuring how much fuel you put in and how many miles you went instead of going by the fuel gauge. That is a much better way of measuring MPG instead of from full to 1/4 marker.

 

[xSojooxShotzx]

On good days, when I do mostly hwy driving, I avg 18 mpg. Mixed, I do around 16 and with mostly city driving I do around 15. I have an upgraded turbo, but fuel and boost levels are all stock. Nothing to be surprised about. AWD cars are gas hogs, and being turbo doesn't help much either

Howie~

 

[timloomis]

Im getting ~230 a tank around town,plus I got 315 miles on the last tank with 1/4 tank used around town,with the rest being 70-75mph cruise.Thats 20psi and all the mods in my profile.I do have a spanking new o2 sensor though,so that may help.But I also have a heavy foot.

 

[1g_tsi_awd]

At least you don't have cold weather... I lose like 20% of my gas mileage in the winter...

 

[Talesin]

I'm still convinced that it's the gearing ratio that does it, possibly with the addition of needing a little more power to get the driveshaft, rear diff and rear wheels turning.
As an example, my GS-T could hit 100mph in third, no problem. The GSX goes up to around 70-80 before it hits redline in third. The GS-T would also regularly get over 400-450 miles per tank, even when romping on it.
There's also the extra weight of the rear portion of the drivetrain that the FWD version doesn't need to deal with, but with how most tend to carry a ton of stuff around, that generally is of lesser impact than the gearing.

It's a tradeoff. Extra stability in turns and better launching, versus gas mileage. If you're willing to shell out a bit more on fuel, a GSX is the ticket. If you're skint and just want to play around on the freeways (or deal with wheelhop and slower cornering) a GS-T is the way to go.

 

[SleepingTsi94]

Well I have only been getting from around 170-200 miles per tank. I expected it to go down with the mods that I have but I see others getting better mileage with more or close to the same. I have replaced the 02 sensor and got 230 to a full tank highway driving. I have also replaced the fuel filter, bottom o-rings of injectors. Checked for boost leaks and what not. Im only going to class and work which are all less than like 8 miles from where I live and on sometimes run to couple other places. I don't drive WOT all time so I know its not my driving. Any suggestions?

 

[xioca]

Thats basicaly what i get to... and I know how it feels. Get a logger and check your fuel trims to see if it's electrical or anything of the sorts. You do a compression test recently?

 

[SleepingTsi94]

Not recently. Motor only has prob 6-7k on it

 

[Cs4g63]

I get about the same mileage. It drives me crazy knowing that on the freeway I get great mileage and around town it takes a dump. But you just got to live with it.

 

[DGajre777]

I get about 200 miles on a full tank, but then again I drive crazy. I have a new front o2 sensor and fuel filter. I know I'm running rich though.

 

[nycxjoey]

I get 230 to 250 miles on a full tank.(All highway miles though )It last me for about a week.

 

[bob123131]

I get about 150 , but i have a little low compression in cylinder 2 and run a little on the rich side.

 

[link16]

i dont know exactly how many miles i get ill check it but on a full tank, i have a loose rod bering, i usually get a good 2 weeks of driving in and i drive a TON

 

[MaxPSITalon]

I get about 225 miles with 10 psi.

i dont know exactly how many miles i get ill check it but on a full tank, i have a loose rod bering, i usually get a good 2 weeks of driving in and i drive a TON

Loose rod bearing? Good luck with that

 

[eboy0]

I get about 160 miles to a tank, and thats driving around in vacuum the entire time... some highway and idling at 800..... new O2 sensors and stuff, DSMLink aswell.

 

[SleepingTsi94]

Hmm guess im not alone. Just thought it was kinda bad to see full size trucks getting better gas mileage driving around than what I was getting. Guess I was over expecting

 

[hybridb18]

i have always averaged about 20mpg ever since i bought my AWD. this is about half highway and half city driving. i have just a bunch of basic bolt ons nothing crazy. my gas light comes on at about 260-270 miles on the tank, thats usually 13-ish gallons... i usually run 93 Shell, or 94 Sunoco if that says anything

 

[gdmbat85]

It's most likely the cold weather, if you've noticed the change durning the winter. I drove down to florida this week. My car got about 200miles to the 1/4 mark on the first tank. By the time i got down there it was getting about 250miles to the 1/4 mark. The colder the ambient temperature, the more oxygen molecules in the air. ECU sees more oxygen so it adds more gas to keep a stoich mixture. And a little side note: Don't drive to florida unless you have a co-pilot capable of driving manual.

 

[FenixTX717]

well with my 1st 2gen talon with basically full exhaust, upper and lower ic piping, intake, MBC set at 14lb....

i was getting like 320 highway miles....full tank of gas....and i got to about 340 a couple times but that was pushing it....

but my spyder with the same mods gets about 260 highway....i dont' get it!

 

[evogst97]

Well I have only been getting from around 170-200 miles per tank. I expected it to go down with the mods that I have but I see others getting better mileage with more or close to the same. I have replaced the 02 sensor and got 230 to a full tank highway driving. I have also replaced the fuel filter, bottom o-rings of injectors. Checked for boost leaks and what not. Im only going to class and work which are all less than like 8 miles from where I live and on sometimes run to couple other places. I don't drive WOT all time so I know its not my driving. Any suggestions?

If you tune check your fuel trims and lean stuff out.

Dont go crazy and cause worst problems though. Also when doing the boost leak test did you have the throttle open? Was the mbc tightened to the point where it would hold enough boost? Just a couple things to check.

 

[link16]

well with my 1st 2gen talon with basically full exhaust, upper and lower ic piping, intake, MBC set at 14lb....

i was getting like 320 highway miles....full tank of gas....and i got to about 340 a couple times but that was pushing it....

but my spyder with the same mods gets about 260 highway....i dont' get it!

Spyder's are way heavier, I don't know exactly but if memory serves me correctly, around 800lbs heavier.

Back to the OP I filled up and have driven about 80 miles and I rest at 3/4 tank, I have a 12.5 gallon tank. I have a ram air intake resting at the opening in my carbon fiber hood.

Only N/T for another 3 weeks, we shall see after that.

 

[Spoolin4Ever]

Well I am suprised how bad some of us have it. I have a 1G AWD, and commuting which is a combo of some crappy rush hour, city and highway both, I got about 280 on a tank when I was running some Chemtool B12 in the gas, and I had Redline 10W30 Oil. Last tank was 10W40 Redline and a little acetone in the gas, 230 in a tank.

But just as a general rule I get from 230 to 280 commuting.

If I do a long highway trip I can get about 300-320 a tank...depends on how I drive and what speed.

What I wanted to say though is once I got only 180 in a tank, and at the time I had a leaky fuel injector. One way to tell is when you turn the car off, you smell raw gas (injector was leaking fuel from the fuel pressure left in the system). Also this would make the oil level rise, because the gas would go down past the rings, into the oil. VERY BAD. If this happens change your oil ASAP... run cheap oil till you get it fixed so you can change frequently.

Another thing: maybe carbon buildup on the piston tops. Soak the pistons with MMO...etc search google for more info on that.

And of course the general tuneup..plugs, wires, etc..

 

[EagleTalonTim]

I am able to get around 320 per tank in the city, and around 370 on long trips. I once got a little over 400 miles on one tank. No really big mods, just a Cold air intake, open box K&N, header with 2 1/2 exhaust pipe to the muffler. I run Royal Purple 10-30 in the summer and 10-40 in the winter and I also use NGK spark plugs with 10mm wires. I use exxon low grade fuel. I deliver pizza's in it and can go 3 or 4 days on 1 tank