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What's the worst gas mileage you've gotten in your Legacy?
Posted: Fri Dec 08, 2006 3:23 pm
by High PSI
I think you would be hard pressed to beat me. I just filled up yesterday. Put in a bit over ten gallons of gas after driving about 135 miles. Came out with an average MPG of 12.8.

This is with about 75% highway driving!
I have a 318AWHP Eclipse, V8 Camaro with gears low enough that it runs at 3,500rpm at 75mph, and a Lexus SC300. I also used to have an 81 Ford Fairmont that didn't have an overdrive. I drive them all hard, and none of these cars have ever come CLOSE to that poor of mileage!
Obviously somthing is up. The car runs beautifully but throws a CEL on occation when I'm cruising on the highway. I'm thinking either the O2 sensor that came on the exhaust I installed is bad, or the car REALLY doesn't like running w/ the HKS SSQV vented to the atmosphere. Last year before the slew of mods I did, I would pull off about 24mpg on average. Probably doesn't help that, with the 3" exhaust, everytime I even think about touching the gas pedal, I instantly have 12lbs of boost in my intake manifold.

Posted: Fri Dec 08, 2006 3:56 pm
by Innovative Tuning
About 12 gallons in 60 miles of competitive driving (5 MPG).
Posted: Fri Dec 08, 2006 4:02 pm
by Manarius
19MPG courtesy of cold weather, 20-50w and donuts in the snow.
Posted: Fri Dec 08, 2006 4:46 pm
by High PSI
Innovative Tuning wrote:About 12 gallons in 60 miles of competitive driving (5 MPG).
Ok, that'll beat me.
Posted: Fri Dec 08, 2006 7:06 pm
by Legacy777
Check the ECU for what codes have been stored
www.surrealmirage.com/subaru/engine.html
Posted: Sat Dec 09, 2006 3:03 am
by BSOD2600
Try 10.3 mpg over 37 miles (maybe too short to get an accurate/average mileage?). Thats with a dying 4EAT and 4300ft of pure city driving.
Posted: Sat Dec 09, 2006 3:10 am
by Bheinen74
you need to check your code. This past summer, my 93SS would at times run really awesome, and other times it would bog down, like running only on 2 cylinders. I also had the sporadic CEL, was for Canister Purge control solenoid. I also had a weak coil, causing low spark, and when it was running rough, I hit about 9MPG.
So, have you checked the coil, in addition to your code. Once i switched coil, and the solenoid valve, I was again getting 25mpg.
Posted: Mon Dec 11, 2006 10:56 pm
by Brat4by4
4-5 mpg at the track. Something about gaaaaaaaass brake gaaaaaas brake! that really kills your mileage.

Posted: Mon Dec 11, 2006 11:04 pm
by Murphy
i dont driver hard or anything, the worst ive get is when i drive around town alot, it goes to about 25-26mpg
Posted: Mon Dec 11, 2006 11:27 pm
by 206er
got around 17 when my car was still 4eat and beating on it in the snow.
Posted: Tue Dec 12, 2006 2:34 pm
by High PSI
Josh-
Thanks for the link. I'll try to check my codes within the next week or so and I'll let you know what I find. More than anything, now I finally know what those green and black connectors under my dash are for. When I first saw them a year ago or so, I connected them, and when I saw my CEL come on, I thought that maybe the previous owner disconnected them to keep the light off. Glad I know what they're for.
Bheinen74 -
I actually replaced the coil last year with a diamond coil pack. When I did the change then I noticed no difference in drivability or gas mileage. Over this past October/November I installed an MSD DIS-2 amongst my "slew of mods". Since then the car has run much smoother (with the partial throttle hesitation I used to experience all but gone), so I find it hard to believe the car has an ignition problem running the way it has been. I could always disconnect the MSD DIS-2 and see what happens, as I installed it in such a way that I can run the stock ignition in 20 seconds if need be.
I just drove the car over the weekend BABYING it the entire time (accelerating insanely slowly onto on ramps, off of lights, etc.) to the point where I tried to avoid creating any boost what-so-ever (which I found to be impossible...the turbo spools and creates boost under almost any acceleration). Even so, the best I could muster was 18.3mpg - much better, but still far below where I was last year driving the car much harder. I'm hoping the CEL sheds some light on the proble and it's not just that, even when I'm crusing on the highway at a steady 75mph, I'm still averaging about 1psi in the intake manifold.
I've never desired lag so bad in my life.
Posted: Tue Dec 12, 2006 6:27 pm
by BSOD2600
heh, well it turns out the reason why I'm getting such crappy mileage is because cylinder #4 has 10 psi! Getting that fixed this week... *sigh*
Posted: Tue Dec 12, 2006 7:41 pm
by High PSI
Errrr.....hopefully my problem is an easier fix than yours. Good luck with allll
that.

Posted: Sat Dec 16, 2006 8:29 pm
by John Drivesabox
15.7 over the last 2 years in town.
Posted: Tue Dec 19, 2006 1:11 am
by Richard
Zero. I have let my car idle while parked from time to time.
Posted: Tue Dec 19, 2006 3:29 pm
by Manarius
Well, I managed a new low. 17.59 mpg on the last tank (14.66 gallons on 258 miles). Something about revving the engine to keep it from vibrating so badly really kills the gas mileage.
Posted: Sun Dec 24, 2006 4:09 am
by wiscon_mark
21mpg
No seriously.
Posted: Sun Dec 24, 2006 8:28 am
by Flip_x
um the worst was it was a full tank and going about 15-20 miles it went to 3/4 of a tank!! going uphill and keeping it in low gear going up about 70-85mph!!
Posted: Sun Dec 24, 2006 8:46 am
by MPtyza
The worst mileage I ever got in my Turbo was a constant 13mpg. This was when the IAC valve decided to crap out on me, for the month before I got my new IAC valve. The day it came, my engine blew on me while going uphill