Gas mileage please help!
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This is a discussion on Gas mileage please help! within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I bought my 2002 WRX brand new 4 years ago. About a year ago, my gas mileage dropped off tremendously. ...

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    Gas mileage please help!

    I bought my 2002 WRX brand new 4 years ago. About a year ago, my gas mileage dropped off tremendously. It did not coincide with anything done to the car and it happended fairly quickly. I have no after market mods... I drive all highway miles-- 200 miles to and from work on the interstate. I am getting about 19 to 21 MPG. I used to get much more than that, I'm not sure exactly what I used to get, but I know that when I've driven to Florida and back from Connecticut I was probably going almost 400 miles without filling up. Now I'm lucky if I get 280 miles (all highway going 65 MPH!). I've brought it to 3 separate mechanics and the Subaru dealership (I was desperate)---had every diagnostic test done, changed filters, adjusted fuel trim, etc etc. Every body is stumped, including myself! Has anybody had this problem or have any suggestions? Thanks!

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    had a compression test done? how many miles? you said youve done all the regular mainenance stuff.. so im not sure
    14.160@96.011
    90 degree weather
    airhog, removed silencer, and removed stock catback exhaust (stock DPs in place) and craptacular california 91 octane piss water

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    Registered User dcpatters's Avatar
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    What about alignment and tires? Tire pressures?
    2008 Evo X GSR. Custom tuned, Works panel filter, Intercooler pipe upgrade, TBE.

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    Quote Originally Posted by dcpatters
    What about alignment and tires? Tire pressures?
    true! is there junk in your trunk? did you go an abnormally long time between oil changes?
    14.160@96.011
    90 degree weather
    airhog, removed silencer, and removed stock catback exhaust (stock DPs in place) and craptacular california 91 octane piss water

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    Quote Originally Posted by blackrex02
    had a compression test done? how many miles? you said youve done all the regular mainenance stuff.. so im not sure
    The compression test is a good idea---I haven't done that yet. If the compressions are off, what next? The car has just about 60,000 miles on it. As far as tire pressures and oil changes go, well--I'd have to be a fool not to have thought of that already! This is almost a 10 mpg reduction, so its something big. I was also thinking it could possibly be the injectors. I don't know too much about those but I was told it is hard to test a fuel injector.

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    Check and clean MAF sensor, check o2 sensor. Check or replace knock sensor, when mine went, I lost some big time gas milage. Car still seemed to run OK, maybe just a little less power... but when I changed the knock sensor out then I noticed a major improvement in gas milage and some power gain.
    '02 WRX 4EAT, 311,000KMs/194,500Miles, Sold. Best car I ever had. '09 STi stage 1, hope this one will be good too...

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    Registered User Droopy's Avatar
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    I get about 19 to 21 in my 02. I always have with mixed driving 24 or 25 with pure freeway. I try to get about 300 miles out of a tank. I used to use premium now I use mid grade with the same result.

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    Quote Originally Posted by Droopy
    I get about 19 to 21 in my 02. I always have with mixed driving 24 or 25 with pure freeway. I try to get about 300 miles out of a tank. I used to use premium now I use mid grade with the same result.
    Yeah I used to use 93 octane I find that 91 is just as good but around here its hard to find 91! So I pay my $3.20 for 93 and try not to think about it.
    I'd be happy with 24-25 but my 19-21 is pure freeway. I get about 18 city. I did add some expensive fuel injector cleaner and I got about 24 mpg for about 2 tanks but then it dropped back down again.

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    Quote Originally Posted by wrxdrvr
    Check and clean MAF sensor, check o2 sensor. Check or replace knock sensor, when mine went, I lost some big time gas milage. Car still seemed to run OK, maybe just a little less power... but when I changed the knock sensor out then I noticed a major improvement in gas milage and some power gain.
    How much did the knock sensor cost?

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    Quote Originally Posted by chemical09
    How much did the knock sensor cost?
    It cost me 125$ but that's Canadian, so it should cost you less.
    '02 WRX 4EAT, 311,000KMs/194,500Miles, Sold. Best car I ever had. '09 STi stage 1, hope this one will be good too...

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    Quote Originally Posted by chemical09
    Yeah I used to use 93 octane I find that 91 is just as good but around here its hard to find 91! So I pay my $3.20 for 93 and try not to think about it.
    I'd be happy with 24-25 but my 19-21 is pure freeway. I get about 18 city. I did add some expensive fuel injector cleaner and I got about 24 mpg for about 2 tanks but then it dropped back down again.

    3.20 for 93?>!?#@!@ im paying like 3.70 for 91.... stupid san diego!

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    my car is an 02 as well...and i always get 300 on a tank and tops like 320 b4 the warning light goes off...u say changing the knock light wud improve mpg...i guess were all looking for ways to imrpove milage w gas being ridiculous!!!

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    my car is an 02 as well w 43k on it...i get usually over 300 but the warning light will go on probably around 320...u sed changing the knock sensor wud improve gas milage...w gas prices today i guess were all looking for ways to get better mpg....its ridiculous!!!!

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    wantd to change knock light to knock sensor...silly me

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