ljshein Posted March 26, 2013 Share Posted March 26, 2013 99 legacy GT automatic with 111K miles, when I got the car 2.5 years ago it had 80K miles. When I first got the car, I was getting 29 mpg on a long trip, 22/23 with my normal commute, I went on a long trip this past weekend and only got 22, it's been running 19/20 for my normal commute. It concerns me that the mileage has been slowly declining. I've done plugs, wires & filters, made sure I've got 35 lbs of air in the tires... No oil leaks, timing belt was done at 100K. I've replace one CV boot (did it the correct way) and the rest of the boots are in tact. No drivability issues to speak of. Any suggestions or is this what I should be expecting for the car? thanks! Jeff Link to comment Share on other sites More sharing options...
mattmattyxcore Posted March 26, 2013 Share Posted March 26, 2013 Check your intake for any leaks. If it's getting any extra air it will add fuel. Link to comment Share on other sites More sharing options...
snederhiser Posted March 26, 2013 Share Posted March 26, 2013 Hello; I try and buy a good grade of gas that has fuel system cleaners blended in. Try some seafoam, or techtron. Have you cleaned the MAF? How are the O2 sensors? Vacuum leaks are another killer, Steven. Link to comment Share on other sites More sharing options...
Sludgeroo Posted March 26, 2013 Share Posted March 26, 2013 Vacuum lines like Steven said, or also which ties in with vacuum, check to see conditions of plenum and intake mani gaskets. Small cracks stand no match for vacuum Link to comment Share on other sites More sharing options...
cavemanauto Posted March 27, 2013 Share Posted March 27, 2013 Sorry to interject, but aprox how many miles is a tank good for? I have a 97lgt 5spd and in town I get 220 long trip I get close to 300. Is that the norm? Thanks Link to comment Share on other sites More sharing options...
InsertEnigmaHere Posted March 27, 2013 Share Posted March 27, 2013 Sorry to interject, but aprox how many miles is a tank good for? I have a 97lgt 5spd and in town I get 220 long trip I get close to 300. Is that the norm? Thanks I personally get around 240 around town with some stop & go. On the highway, I get about 350 miles until the light comes on. Link to comment Share on other sites More sharing options...
ChaoticZen Posted March 27, 2013 Share Posted March 27, 2013 Check Fuel filter, and 2.5 years ago you might not be using that ethanol junk that we are all forced to use...if you still can, find a gas station around you that still sells gas with no ethanol and give that a try... Sent from my SCH-I535 using Tapatalk 2 Link to comment Share on other sites More sharing options...
ljshein Posted March 27, 2013 Author Share Posted March 27, 2013 thanks guys, did the fuel filter, did the techron. caveman, with the current mileage, I'm about 280 per tank around town, it used to be about 315. I do run it right down to the empty mark... usually running it down to about a gallon left in the tank. I'll check for vacuum and clean the MAF. A few tanks of seafoam sound like a good idea, that stuff will clean out the whole intake system. I don't think the O2 sensors have ever been touched... I'm probably past the normal life span for those. I did notice a drive-ability issue this morning, it was about 35 degrees out this morning and after 10 miles, the engine was still idling a little high at the first light I stopped at. Kind of like the cold start was still on. I know cold start pushes a lot more fuel in the system which would cause the poor economy. I had to shift to neutral and let the idle settle and after that it was a normal 700 rpm idle. I guess I'll have to break out the book and see how to test that system. thanks! Link to comment Share on other sites More sharing options...
snederhiser Posted March 28, 2013 Share Posted March 28, 2013 Hello; Check the water temp sensor. This has two prongs and the last one I replaced cost me $14.00. Steven. Link to comment Share on other sites More sharing options...
530ras Posted March 30, 2013 Share Posted March 30, 2013 my 07 lgt with 138k gets about 250 a tank, but i just did a tune up and some other stuff so well see if I get any better. Link to comment Share on other sites More sharing options...
spooln30 Posted April 5, 2013 Share Posted April 5, 2013 What most people don't know is when the gas stations switch to the "winter blend" gas your fuel mileage will decrease. Now from the info I've read over the years almost every state except CA switches gas blends. I have always noticed my mpgs get lesser during the winter months. With our cars getting less mpgs from the get go it will be more noticeable because they don't get very good mpgs yo begin with. Link to comment Share on other sites More sharing options...
spooln30 Posted April 5, 2013 Share Posted April 5, 2013 Well I just looked and every state uses a winter blend gas. Just to clarify. Link to comment Share on other sites More sharing options...
Bassnectar Posted April 5, 2013 Share Posted April 5, 2013 Yep winter gas will remove mileage for sure! it makes my tercel go from 620KM/ a tank to 570Km/tank sorry Its in KM my Wrx is in miles and I haven't ever driven it to E. Don't run your car that empty in the first place!! as your tank nears empty all the contaminants from bad gas or rust in the gas tank itself gets shot right to the engine! hopefully getting stopped by the fuel filter.. but some will always get through. its the same reason you shouldn't fill up while a tanker is unloading at a station, because it swishes the stuff at the bottom of the tank around. Change your fuel filter, and check for vacuum leaks by spraying the connections of your vacuum hoses with carb cleaner, if there is a leak your RPMs will rise as you have added fuel to the mix. (use your ears) Run a fuel cleaner such as Redline sl-1 or Regane Gumout, any cleaner that contains PEA will actually clean your injectors, and fuel system better than seafoam in the gas. If you wan't to calculate mileage there are free apps for your Iphone / Android / probably blackberry that will calculate it for you based on entering the info on your receipt. it will be more accurate than the cars fuel gauge anyway. Link to comment Share on other sites More sharing options...
monkeyposeur Posted April 6, 2013 Share Posted April 6, 2013 Your gas tank holds 15.9 gallons. I get about 23 mpg city driving like an @@@hole. Highway at 70 mph I have gotten up to 32. Link to comment Share on other sites More sharing options...
spooln30 Posted April 6, 2013 Share Posted April 6, 2013 Dude 32mpg at 70 mph I don't think so. The faster you go the worse the mileage. The best mileage I've ever got was in my 96 L with the 2.2 on a long road trip and even then I didn't get 30mpg and I dove very conservatively. Link to comment Share on other sites More sharing options...
Zues Marine Posted April 6, 2013 Share Posted April 6, 2013 anybody use this? i've had it on my android for a year or so.. not too bad http://www.fuelly.com/ Link to comment Share on other sites More sharing options...
spooln30 Posted April 8, 2013 Share Posted April 8, 2013 Figuring out your mpg is really just fill your tank and reset your trip then drive till the tanks on E. Say you got 350 you divide it by 15.9 and you would've got 22.01 mpg. Right now with the winter blend I get 75-80 miles per 1/4 tank, which really sucks. LOL. Link to comment Share on other sites More sharing options...
PorkchopSandwiches Posted April 8, 2013 Share Posted April 8, 2013 I use an OBD II scangauge ii to read fuel economy and I tend to get about 25mpg going 70mph on the freeway. Around town it's more like 20. I haven't run fuel system cleaners yet but I plan on it next time I fill the tank. Link to comment Share on other sites More sharing options...
Kiyo1990 Posted April 8, 2013 Share Posted April 8, 2013 I am in a similar boat. Very true, winter blend will kill milage. As well, I normally get 220-240 a tank and sadly that's a good bit of city driving. I used to get over 300. Time to check for lake at intake...haven't found a leak yet actually. Newer wires and coil pack, fuel filter and air filter. I also did a whole exhaust, headers back, and a new front o2 sensor. Plugs should probably help lol. But good thing summer is almost here. Lets see how this gas switch helps Link to comment Share on other sites More sharing options...
Fire Away Posted April 9, 2013 Share Posted April 9, 2013 Over the last 500 miles I averaged a hair under 27mpg. Mostly highway with the speed between 60 and 75 depending on the road. I did the fuel filter, air filter, ran Lucas fuel system cleaner, and cleaned the MAF/TB during that time period so this next tank should give me a better idea of what MPG I am going to get. I am also running the tires at 36psi. Link to comment Share on other sites More sharing options...
Zues Marine Posted April 9, 2013 Share Posted April 9, 2013 maybe you should reset your ECU, let it re-learn your driving habits with the summer gas blend and new stuff installed Link to comment Share on other sites More sharing options...
Fire Away Posted April 9, 2013 Share Posted April 9, 2013 I would assume we have summer blend gas in my area by now but who knows given the cold weather we have had up until today. I may reset the ECU at the end of this tank (have about 200 miles left in it give or take) and see what that does. The PO also installed 16" WRX wheels and I'm not sure what the aspect ratio on the tires is. That could be skewing my numbers slightly. 2500rpm is ~58mph in 5th gear. Link to comment Share on other sites More sharing options...
Bassnectar Posted April 9, 2013 Share Posted April 9, 2013 QUIT DRIVING YOUR TANKS TO E... you clog the fuel filter much faster when you allow the fuel pump to suck up the debris at the bottom of your tank... Sure it allows easier calculation of MPG... but clogging the filter only lowers your MPG faster.. Fuelly is a great app you put in your price of gas / amount and it will calculate your MPG, Cost per mile and keep a track of your total fuel costs. Taking the easy way and driving it till the gas light go ahead.. But test the fuel pressure before & after the fuel filter now and then again in a year and I bet you will have lost some Link to comment Share on other sites More sharing options...
Fire Away Posted April 10, 2013 Share Posted April 10, 2013 I use Road Trip on my iPhone. Here is an example from my Tacoma over nearly the last three years. http://farm9.staticflickr.com/8244/8635324399_4729aa1f4c_b.jpg I used Road Trip LE, which is the free version of road trip for all of that data. I upgraded to the full version when I got my Legacy so I could log two vehicles. As a result, the log doesn't have any expenses such as oil changes, payments, tires, etc. I also have Fuelly but if you don't care about the social aspect of the app Road Trip is much better. Link to comment Share on other sites More sharing options...
Hemingway Posted April 10, 2013 Share Posted April 10, 2013 Omg that is a cool app ... thanks! I also use Decibel 10th ... A free app that you can use for testing sound level. One of the Multi Measures apps. Link to comment Share on other sites More sharing options...
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