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

 

[gstspyder1998]

I drive a 98 GST Spyder and I get about 24-25 mpg on a full tank. That's about 340-360 miles on a full tank.

 

[ASZRAEL1266]

i get 250 miles to a full tank if i do mostly freeway. and about 220 or so on the city so that comes out to about 18 in the city and like 21 on the hwy.

 

[Spyder FX]

I get about 31 on the highway and about 24 city, I drive my little 1.8 hard I guess.

 

[L2RTSiAWD]

I get about 220-230 to a tank.

91oct squirrel piss all city driving.

 

[umiami80]

Depends, I one night I got 180 Miles. Driving home Non stop with the cruise on I got over 400, no boost of course.

 

[greathuskie]

what the hell is wrong, even with a heavy foot i shouldnt be getting this bad of mileage? idont floor it whenever possible either, this really sucks

 

[Kyle90GSX]

O2 sensor is probably taking a crap on you.

 

[doodie]

My 1993 I6 Jeep grand cherokee did 11mph

 

[Megaman]

are u venting to the atmosphere? cuz if u are, it causes bad gas mileage

 

[turbolaserAWDrs]

i get about 15 mpg too, what's involved in replacing the 02 sensor and approx. how much?

 

[TalonESi]

$30-70 for the sensor, and a open end wrench, unscrew the existing sensor, disconnect the harness, screw in the new sensor, connect the harness...done.

 

[TalonESi]

I recommend one from NOPI,

The link get butchered by line breaks when put into html, or vb code, so you'll have to copy and past the parts of the link into your address bar...

http://www.nopionline.com/index.cfm?
fuseaction=dspparts&vL1ID=0&makeid=250&modelid=015&catyear=199
5&catid=0020&pcid=973&vTitle=1995%20MITSUBISHI%20%20%20%
20%20%20%20%20%20%2=0%20%20%20%20%20%20Eclipse%
20Exhaust%20Oxygen%20Sensor

 

[dsmnelskels]

correct me if I'm wrong...but isn't there two O2 sensors? one b4 and one after that cat. I do believe that one is about 60 bucks and the other is like under 20...If i'm right....I know on my old car it had two. I haven't even looked on my eclipse. but they are easy as hell to change providing you have the tools....and a tip....since its located on the exhaust pipe...do it b4 driving or after the car has had a few hours to cool off...otherwise you're going to burn yourself

 

[TalonESi]

The one before the cat is the actually one that the ecu uses to caculate the air/fuel, the one after the cat is not important and only needs to be replace if the CEL comes on, because that's all it's for... if your cat isn't working effectively, it turns on the CEL, ...and once that second o2 sensor is completely ragged out it will cause a CEL too, so I'd just wait for a CEL before I spend money on the in car emissions checker (2nd o2 sen.).

 

[PhoenixRPR]

On my 92 GSX, I'm able to fill her up to about 12.3 gallons. I get about 200 miles per tank. That's 16.26 mi/gal. What kind of gas mileage are you 1G'ers getting and why? Thanks.

 

[TSiAWD91]

im only gettinr around 12-13 i think.thats with mainly normal driving,and a little bit of "sprited".i think im getting low mileage because it NEEDS a tuneup and i have yet to do it.i dont think 15 LBS of boost helps either,but oh well.

 

[PhoenixRPR]

Wow, 12-13 is quite low. Let me know hwo it improved after the tuneup. My car is pretty tuned to spec, so I don't think it's that. I'm running stock boost, stock everything pretty much. My driving habits I would say range from average to 10 mph above average. I don't race it, she's not ready

 

[Ryan86]

Traveled 39 miles today and almost 1/4 tank is gone! wtf?!?! That can't be right, can it?

Is she running too rich? My 16g is set at 8psi and has no fuel mods except for a rewire...should i turn the boost up a bit more?

Any suggestions on why my mileage sucks? Thanx

Ryan

 

[herostar]

you may have a bad front oxygen sensor, this happened to me (it's actually getting fixed tomorrow morning) and I got 130 miles out of 3/4 of a tank... just a thought

why only 8psi, stock boost is like 10 or 11

 

[PhoenixRPR]

Originally posted by TSiAWD91
im only gettinr around 12-13 i think.thats with mainly normal driving,and a little bit of "sprited".i think im getting low mileage because it NEEDS a tuneup and i have yet to do it.i dont think 15 LBS of boost helps either,but oh well.

Well I wanted to update my gas mileage status. I have modified my driving habits and have made a big increase in mileage. I not get at least 20 mpg city/highway combined. So those of you getting 16 or less mpg, you have a lead foot. Don't take it personally, I had it too. Shift no later than 3k RPMS at every gear and notice the difference. Peace.

 

[PaulyMags]

There may be another simple reason why some of you are getting bad gas mileage. Check and see if your engine is warming up sufficiently. If not, you may have a bad thermostat that won't let your engine warm up, therefore, causing your engine to drink lots of gas. I gotta replace my thermostat soon.

 

[iisbernhard]

i get bout 360 miles on 12 gallons....CITY....YEET...gotta love the 1.8's

 

[4g63tc]

i get around 280mpg and that's mixed city/highway (this is with new o2 sensors)
I used to getaround 200mpg with the bad ones

 

[echo]

i get about 250 miles on 93 driving city and highway, but more city.

 

[talontsiawd05]

i know this topic has been brought up many times, but ive been getting horrible gas mileage. i am venting to the atmosphere, but my car does not idle funny or have surges like poeple said it might. if this is the most likely problem can someone tell me EXACTLY where to run the tubing from the bov to, i know its the intake, but where!?, my car came vented when i bought it. also it makes these flutter noises when i let of the gas from 2k-6k rpms, after that i just get the psshhhhhhhhhhht bov sound. right now i have the stock bov and am upgrading soon. i really want the new one to vent so im thinking about the turboxs rfl. i love the sound of a vented bov, cept mine is fluttering! another thing is my passenger side window doesnt work, it has a couple times from the drivers switch, but would work opposite as pushed, ie push down and it would go up. now it doesnt work at all, no its not the motor. just wondering if anyone knows how to make these fixes that could tell me. sorry that was so long and boring
THANKS