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

 

[wangboy925]

Dam you guys all on here get terrible gas mileage. I get 32mpg (normal driving)(70% highway, 30% city)

 

[PIMking]

hwo do you check timing on these cars without a scan tool?

ground the timing port in the engine bay then take a timing light and see what the base timing is on the crank pulley.

To adjust take the nuts on the cas loose and rotate it either way until your at 5*

 

[snakeyes711]

Search the spark plug faq thread, with a 16g there's a 99% chance that you aren't going to need a colder plug than the bpr6es. The faq has heat ranges explained pretty thoroughly, I'd link you but I'm on my phone.

Right on. I'll link it.

http://www.dsmtuners.com/forums/frequently-answered-dsm-questions/233421-spark-plug-faq.html

I'd say his car would run great on some bpr7's but he might just, try them both out to see which is better for his car. Mine liked the colder bpr7. I may have a bit more done to this car them he does.

 

[boostedgsx95]

these cars are suppose to get about 20 miles per gallon. from full tank to a quarter of a tank i get 140 miles, just threw a code couple weeks ago for the o2. changed that and the thermostst. still get the same horrible gas mileage. any suggestions would be greatly appreciated. thanks alot

Dylan

 

[acdavis25]

Check for leaks in your fuel lines.

 

[boostedgsx95]

Check for leaks in your fuel lines.

ok ill try to get it in the air this week. but ive NEVER seen any gas drip or leak or any puddles under the car if that says anything. could the fuel filter be the problem?

 

[94'TSI'AWD]

So, i have had my car for about 4 months now and it consistently gets about 10mpg in town. I have done a complete tune up on it since may. (all new belts, COMPLETE fluid flush, Plugs are good...etc) I have seafoamed it, and tried injector cleaners But it is not getting better at all. I was wanting to check the O2 sensor but from my understanding, there is no way to check one so i kinda just have to fork out another $110 and hope it works. Can you please direct me on were to go with this problem. And if i am getting 10mpg on summer gas....ugg I don't even want to know what i will get on winter gas.

Please advise!

 

[Kastigir]

Spark plug, Spark plug wire, spark plug gap, spark plug cross reference and ignition wires at Sparkplugs.com

OE Denso is $54

 

[zhjiln]

10mpg is ...... biggest problem is your right foot ...


i get 21 city/ 29 hwy . .... boost is taboo with my eco style...

 

[lacroixdp]

10MPG isn't too bad at all. All 4 of my DSM's have gotten that in the city. If I'm easy on them I can get 13MPG. As a matter of fact, I take great pride telling Prius drivers how awful my mileage is. As soon as I convert to E85, I can't wait to start telling them I get 6MPG in the city!

 

[jrohner]

10MPG isn't too bad at all. All 4 of my DSM's have gotten that in the city. If I'm easy on them I can get 13MPG. As a matter of fact, I take great pride telling Prius drivers how awful my mileage is. As soon as I convert to E85, I can't wait to start telling them I get 6MPG in the city!

That sucks. The worst I ever get on E85 is 16mpg short trips / ripping around, and I drive hard. These cars suck for mileage if you're on the stock tune and especially driving hard on the stock very rich tune.

I was wanting to check the O2 sensor but from my understanding, there is no way to check one so i kinda just have to fork out another $110 and hope it works.

Either get a logger or you can just hook a couple wires up to your o2 and use a volt meter to see if it's cycling up and down (meaning it's working and in closed loop mode). If a regular o2 would cost $110 (you're getting ripped off if so), just get a wideband (Innovate LC1) for a little bit extra. You can hook the wideband up to your ECU and get better mileage since it heats up in less than 30 seconds and you can even lean out closed loop for an extra boost in mileage.

 

[Rob10_99]

Very rich and ripping through gears in the city? block to block stop and go? that's tough for anything but cars like a prius that stops the engine.
Leaning out is the first thing, you will need a new sensor, that sounds like your problem.
Don't have a wideband or tuning?

 

[scottiesoccer1]

I get a consistant 27-31 MPG doing your average daily driving a little highway and a little city. Im running the stock tune with a 14b ported and thermal 3" turbo back. I drive the car pretty hard too. I love playing. At WOT my air fuel is about 10.8 thats on the stock tune. So i could only imagine the mileage I could get if it was tuned a little leaner.

Scott

 

[habitatguy187]

Buy a Haynes manual from ebay and a $3 voltmeter and test your o2 sensor.

 

[94'TSI'AWD]

I dont drive my car in boost all the time, nor do i tach it out stop light to stop light. I drive it pretty conservatively everywhere i go. But still 10mpg is horrendous. I shift about 3k and dont usually let it get into boost. I pretty much ####y foot around everywhere.

The only aftermarket parts are my 3" turbo back, Open element air filter, BCS is gone, and Aluminum radiator. All which have been added within the past 2 weeks. i have had this gas mileage issue ever since i got the car stock in may.

 

[Silver99GSX]

ive been getting around 17mpg city

 

[DSM1G90]

I'm a 21/28 mpg driver, but still all stock. Just a easy town driver and take it easy on the freeway.. I do best not to hit the boost unless I need it ..

Also, being an AWD, you got an extra "driveline" that the transmission have to turn and that is just plain added rotational resistance for the motor to have to turn-along with that you're heavier than us FWD units. Check out the AWD driveline assembly for any kind of resistance.

Also, being AWD, you got tires the same size, or got some slightly different in diameter. If so, that AWD viscious assembly is working all the time and that really hogs power from the front end and kills mileage .. along with gradually wearing out.

Got any brakes hanging up..? Tires at proper pressure levels?

What size of injectors you got in that thing and if they are BIG, your ECU may not be "tuned" for those larger injectors - why your mileage is being crappy on you.

Some areas to look at ...

-DSM

 

[2gawdtsi]

My gas mileage has dropped recently to around 16 mpg. i can get maybe 180ish out of a tank? i was getting around 20 mpg a month or so ago.

why would it have dropped? the cold startups?

i cant afford this

poor high schooler workin at old navy 10 hours a week. hahahahahaha
which goes almost entirely into gas.

 

[wises4057]

well cold weather will make your mileage drop, but I don't know if its been cold enough for that lately(I live in wisconsin)....is there a check engine light on? could be an o2 sensor going out...

 

[Dsmj89]

I'm surprised none of you have even mentioned tire pressure.
Low/incorrect tire pressure can also take a toll on your mileage, due to the fact the car has to use more force to pull a wheel that's now not easy to rotate, think of it as having a weight on your foot and trying to walk, you will get tired fast. Same idea applies.

 

[2gawdtsi]

yes there is, im not quite sure for what yet though, havent been around a scanner in awhile.
and the gas mileage just barely started dropping.

my thermostat on my car is a 185 i believe instead of the stock 195 if im correct? would that make any difference in the engine warming up on cold mornings? i had the choice to pick between the two and wanted to keep my car cooler in the hot summers.

tire pressure is fine,around 37 psi on all four.

 

[99vipereater]

I get around 17 mpg. Mostly city driving

Thats about what i get in my 99 gsx probably because of warmups in the morn.

 

[One Equals Two]

I'm pretty unhappy with 19 mpg total. I was hoping to be around 23-24 (bone stock Talon TSi AWD). I do mostly freeway driving (60%). But I just chaged the O2 sensor and cleared the CEL so that may help....right?

 

[born2tune]

ok, lets put it this way, whos getting good gas mileage??!?!?!

 

[2gawdtsi]

the N/T guys