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

 

[Jake1987]

Get a Denso o2 sensor. I just ordered one on Amazon. FREE shipping and stuff.

 

[1killerEVO]

Yeh sounds like a bad o2 but also make sure your FPR is operating properly.

 

[Dsm304]

Just curious on how much gas mielage does everyone get out there I have a 95 eagle talon tsi with a some minor upgrades walbro fuel pump evo 560cc fuel injectors and I get around 250 miles a tank 93 octane not sure is thats a good mialege or not????

 

[boostront]

I get about 350 to a tank doing mostly interstate driving,And about 250 in town.I also waste more gas in town with all the stop signs and lights.Mods include evo 560cc injectors,16g turbo,obxr fmic,ecm link v3.lite on 93

 

[And_44]

I had a stock 95 Talon TSi Auto FWD only mod was a Cat delete. But got something close to 340 miles to tank. In city was 23 to 24 in freeway 32-34 mpg. How ever my 1g Talon AWD manual have always gotten 18-24mpg between city and freeway.

 

[GoCanes777]

How heavy is your foot...

I get about 250-275 city add 100 for the highway

 

[Jake1987]

250mpg is not bad at all.

 

[mattasi]

400awhp on my GSX, I get around 16-18 mpg. And that is DDing to work, and some spirited driving mixed in.

 

[Redslayer]

28-32 MPG average o.o That's one good thing about the 420a . The worst I ever got was 26mpg Average, and I did quite a bit of racing on that gas. I've gotten higher than 33 MPG average before, but it usually stays around 28-32 range.

 

[Dsm304]

Haha then im not the only one around the 250's haha I was starting to get worried ### its my dd and so and I do have a heavy foot sometimes and when I do I get about 200 to 225 miles a tank haha and I only boost normal at 10psi still havent figured out if I have a 16g or not since I got the car and its about a year now never taken the turbo out and the code carved to it is hardly understandable.

 

[Boosted DSM 32]

Haha then im not the only one around the 250's haha I was starting to get worried ### its my dd and so and I do have a heavy foot sometimes and when I do I get about 200 to 225 miles a tank haha and I only boost normal at 10psi still havent figured out if I have a 16g or not since I got the car and its about a year now never taken the turbo out and the code carved to it is hardly understandable.

Take off your intake and look at the size of the compressor housing

 

[Dsm304]

Hmmmm it says TDO5H on the cold side the turbine fan on the cold side is wavy 6blade and every blade is like splitted into 2 but their together

 

[WES_393]

Hmmmm it says TDO5H on the cold side the turbine fan on the cold side is wavy 6blade and every blade is like splitted into 2 but their together

Find the turbo ID number on the compressor housing. It should be right behind the intake towards the engine. Post up the number and we can tell you which TD05 you have.

 

[NeWyoRksPLaYaZ]

Mixed city, highway and some spirited runs at a full tank, I get 280/tank.

mainly stock except a few mods, stock fuel system and injectors

 

[Dsm304]

I found these 2 numbers the top one is
8030409077
Bottom is 49178-07900

 

[Abe'sGST]

I get around 350 to a full tank on my gst. I'm not too sure if that's ok? I have stock injectors, just a 14b turbo. Now on my dd saturn, i'm getting 35-38 MPG, so i don't really worry as much with these gas prices going up.

 

[_dOp_skyLINe]

i got 350 miles per tank in city with 550ccs fic and 16g

 

[Dsm304]

Mixed city, highway and some spirited runs at a full tank, I get 280/tank.

mainly stock except a few mods, stock fuel system and injectors

I wished id get that much with my mods haha!!!

 

[Abe'sGST]

i got 350 miles per tank in city with 550ccs fic and 16g

So from this I'm guessing that I'm running too rich, since i have 450cc injectors and a 14b, getting same mileage

 

[lilbp12369]

I'm averaging 26- 28 mpg with about a 50/50 city highway mix of driving. All highway, I am seeing 31-32 on average. Putting down about 320 whp so I am pretty happy with these numbers.

 

[99gst214]

Invest in Link then dude. You would be able to safely lean the fuel trims out for highway driving. The stock tune is nasty rich. I currently dd my 95 tsi awd and get about 300/tank. Only mods are intake, and cat-delete, for now.

 

[Tommy's]

i think my mpg is around 17 right now but thats because i've been running it on idle a lot trying to get it running perfect. my last GST i had i averaged close to 30mpg

 

[Dsm304]

I found these 2 numbers the top one is
8030409077
Bottom is 49178-07900

Sorry guys I gave the wrong number here it is again
Top-8030409077
Bottom-49178-05200

 

[402tuner]

Is your blow off valve recirculating or vented to atmosphere?

 

[lilbp12369]

It does sound like an o2 sensor but if it is it will be throwing a check engine light. Venting to atmosphere will hurt your gas mileage too. Are you up to date on your routine maintenance? Little things such as air filter, spark plugs, gas cap, tire pressure and old oil all have an impact on your gas mileage. Keeping up with maintenance is a great way to prevent and fix a lot of common problems.