JT95 Posted March 1, 2005 Share Posted March 1, 2005 Okay, when I first started driving my Subaru I wasn't very impressed with the gas mileage, but at 24 mpg I couldn't really complain too much either. I've been driving it since this past October. Now I am consistently getting exactly 20 mpg for the past month. These are mostly interstate miles too. I can't live w/ 20 mpg in a 4 cylinder car--AWD or no AWD... The car is a 95 LSi wagon, 2.2 engine and auto tranny. It does have 180,000 miles on it, but the engine runs butter smooth and sounds/drives just as well as it did when I got it. I was in need of new tires--as one was in pretty bad shape--but my mileage has not changed at all after new tires, balanced, and an alignment. The spark plus and the air filter are about 3.5 months old. I went ahead and bought some new plugs and plan to get some new plug wires on the engine as I'm not sure how old these current ones are even though they look "okay". Air filters can hurt mileage, but they should last more than a few months, shouldn't they? I'll go ahead and replace it as well. Anybody else had to deal with the poor mpg gremlin in the Sube? Any tips/ideas? I love my Legacy, but I cannot drive a 20 mpg car... Quote Link to comment Share on other sites More sharing options...
frag Posted March 1, 2005 Share Posted March 1, 2005 I would replace the O2 sensor is it has not been replaced for a couple of years. They often get lazy without triggering a CEL. Quote Link to comment Share on other sites More sharing options...
bearbalu Posted March 1, 2005 Share Posted March 1, 2005 Check thermostat - if it opens too soon and engine runs cooler, it can dramatically impact mpg...Is the temp gauge lower? Quote Link to comment Share on other sites More sharing options...
johnb102 Posted March 1, 2005 Share Posted March 1, 2005 I have a 95 Legacy LSi wagon with 64K miles, and on the highway with just a driver I can get 25 mpg with luck. In actual driving around the city I usually get about 17 mpg, but recently it has dropped to 15. I might need the Oxygen Sensor since mine is the original. The dealer said there are 2 and they cost about $120 each. Is it likely that both need replacement, or does one tend to go sooner than the other. I have no check engine light, and other than the poor gas mileage I have no other symptoms. Quote Link to comment Share on other sites More sharing options...
subeman90 Posted March 1, 2005 Share Posted March 1, 2005 from my experience subarus are horrible in the winter for gas mileage and the automatics seem worse to me too. Matt Quote Link to comment Share on other sites More sharing options...
frag Posted March 1, 2005 Share Posted March 1, 2005 I have a 95 Legacy LSi wagon with 64K miles, and on the highway with just a driver I can get 25 mpg with luck. In actual driving around the city I usually get about 17 mpg, but recently it has dropped to 15. I might need the Oxygen Sensor since mine is the original. The dealer said there are 2 and they cost about $120 each. Is it likely that both need replacement, or does one tend to go sooner than the other. I have no check engine light, and other than the poor gas mileage I have no other symptoms. Without a specific code pointing to the downstream 02 sensor, you only need to replace the upstream one. It's the one that controls the fuel trim. The other one only checks the cat's operation. Quote Link to comment Share on other sites More sharing options...
JT95 Posted March 1, 2005 Author Share Posted March 1, 2005 from my experience subarus are horrible in the winter for gas mileage and the automatics seem worse to me too. Matt See--I thought I was a freak for wondering that this morning on my way to work. My bad mpg directly correlates to the cold weather. I don't know why this would be--not like the a/c is running like August. I honestly thought the new tires and alignment would help, as I had a pretty worn, out-of-whack one that didn't roll true. No difference though in mpg. Handles like a sticky-fingered chimp on a monkey vine though... I'll look into the O2 sensor. Can you get any info on the sensor's status if the car has not flashed a "check engine" light? Called the parts store and they want $92.99 for it. I'd rather throw away a hundred dollars on extra gas over the next 6 months with a bad O2 sensor than spend $100 at once to replace one that may not need replacing. I replaced the thermostat back in November and the mpg was fine after that. Actually averaged 26 one way on a road trip a couple weeks after the install. The temp gauge does the same thing it has been doing since I started driving the car. Quote Link to comment Share on other sites More sharing options...
ballitch Posted March 2, 2005 Share Posted March 2, 2005 they are expensive but try autozone or schucks or knetchs or however you spell it, i needed one for my car and they quoted me like $75 for one that is compatible with all subie o2 sensors, and yes it was a bosch. never go to the dealer to buy stuff man, unless you really like bending over counters. ~Josh~ Quote Link to comment Share on other sites More sharing options...
later, Peter Posted March 2, 2005 Share Posted March 2, 2005 Okay, when I first started driving my Subaru I wasn't very impressed with the gas mileage, but at 24 mpg I couldn't really complain too much either. I've been driving it since this past October. Now I am consistently getting exactly 20 mpg for the past month. These are mostly interstate miles too. I can't live w/ 20 mpg in a 4 cylinder car--AWD or no AWD... The car is a 95 LSi wagon, 2.2 engine and auto tranny. It does have 180,000 miles on it, but the engine runs butter smooth and sounds/drives just as well as it did when I got it. I was in need of new tires--as one was in pretty bad shape--but my mileage has not changed at all after new tires, balanced, and an alignment. The spark plus and the air filter are about 3.5 months old. I went ahead and bought some new plugs and plan to get some new plug wires on the engine as I'm not sure how old these current ones are even though they look "okay". Air filters can hurt mileage, but they should last more than a few months, shouldn't they? I'll go ahead and replace it as well. Anybody else had to deal with the poor mpg gremlin in the Sube? Any tips/ideas? I love my Legacy, but I cannot drive a 20 mpg car... The gas/oil companies are required to use more ethanol or is it methanol in the winter... this also decreases mileage & also decreases emissions... (do they cancel each other out? I wonder).... I'd try a can of Seafoam to clean things up a bit & maybe tankful of + or premium gas... then again & new o2 sensor might just resolve the whole deal... I once had a hg leak (Isuzu Trooper) into the O2 sensor & the mechanic took it out blew it with compressed air & told me " it may work for awhile"... that was nearly 4 years ago. Later, Peter Quote Link to comment Share on other sites More sharing options...
johnb102 Posted March 2, 2005 Share Posted March 2, 2005 How hard is it for an inexperienced mechanic to replace an oxygen sensor in the driveway? I have ramps and assorted socket wrenches. Quote Link to comment Share on other sites More sharing options...
GLCraig Posted March 2, 2005 Share Posted March 2, 2005 I don't know why this would be--not like the a/c is running like August. If you have the climate control set to defrost, the A/C compressor will cycle on and off but not a frequently as it would if it was set on A/C. This actually helps to suck some of the moisture out of the air. Quote Link to comment Share on other sites More sharing options...
JT95 Posted March 2, 2005 Author Share Posted March 2, 2005 Yeah, I try to make sure I don't have the defog button pressed unless truely needed--I usually run the mixture setting of floor/windshield, which isn't supposed to activate the compressor. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted March 2, 2005 Share Posted March 2, 2005 winter gas decreases mileage.....my '90 Legacy dropped from 28mpg to 24....happens every year. Quote Link to comment Share on other sites More sharing options...
shimonmor Posted March 2, 2005 Share Posted March 2, 2005 I also "second" the O2 sensor idea. If it's never been replaced...replace it at ~100k miles! I changed mine (never got a CEL) and the Sub ran A LOT better. Smoother idle and better mileage. It's pretty easy to change. It's at the front of the cat converter on top. Unplug the harness, use a 22mm (I think) wrench and yank it out of there. The new one should have some aniseize on it already (mine did). And get the one with the OEM plug so you can plug right in. You can buy ones with the bare wires but now you have to splice and dice. Spend the extra couple of bucks for ease of install. Quote Link to comment Share on other sites More sharing options...
bearbalu Posted March 2, 2005 Share Posted March 2, 2005 Okay, before I get off the thermostat horse, how much TIME does it take the engine to warm up? If it takes longer, it would still point to thermostat. If it takes almost same time, may be it is okay. If you are taking a lot of short trips (that don't add up to a lot of miles), you would still be expending a lot more fuel since engine is running cold... How about a trip to warmer south to see if the problem goes away Quote Link to comment Share on other sites More sharing options...
JT95 Posted March 2, 2005 Author Share Posted March 2, 2005 I'll put the O2 sensor on hold until I have the spare cash to pick one up. I'm gonna pull my air filter and see what it looks like. Been busy the past few days, it's terribly cold out, and I have no garage, so I've been lazy and haven't looked yet. It's only 4 months old, though. As far as short trips and warming up, I drive 30 minutes on the interstate to work and then 30 minutes again to get home. I've never really noticed a significant decrease in gas mileage in the winter with other cars I have owned, but then again I watch the Sube a bit closer and probably anyway so due to expensive gas prices. Thanks for all the responses. If I track anything down I'll let you know. Quote Link to comment Share on other sites More sharing options...
jamal Posted March 2, 2005 Share Posted March 2, 2005 My mileage has actually been way up lately. Taking the roof rack off and putting a few extra PSI in my tires definitely helped. I was reading the other day that the recommended pressure on my door is a little low for modern tires and such. Now instead of 30/29, I've got 34/33. I could probably go higher. On a trip from LA to the Bay Area, I managed to get 25mpg with three passengers and our luggage for a weekend, driving 90mph (seriously that's how fast people go on that stretch of the 5). From here: Tyre pressure and gas-mileage. For the first two years of our new life in America, I'd take our Subaru for its service, and it would come back with the tyres pumped up to 40psi. Each time, I'd check the door pillar sticker which informed me that they should be 32psi front and 28psi rear, and let the air out to get to those values. Eventually, seeing odd tyre wear and getting fed up of doing this, I asked one of the mechanics "why do you always over-inflate the tyres?" I got a very long and technical response which basically indicated that Subaru are one of the manufacturers who've never really adjusted their recommended tyre pressures in line with new technology. It seems that the numbers they put in their manuals and door stickers are a little out of date. I'm a bit of a skeptic so I researched this on the Internet in some of the Impreza forums and chat rooms and it turns out to be true. So I pumped up the tyres to 40psi front and rear, as the garage had been doing, and as my research indicated. The result, of course, is a much stiffer ride. But the odd tyre wear has gone, and my gas-mileage has changed from a meagre 15.7mpg (U.S) to a slightly more respectable 20.32 mpg (U.S). That's with mostly stop-start in-town driving. Compare that to the official quoted Subaru figures of 21mpg (city) and 27mpg (freeway) and you'll see that by changing the tyre pressures to not match the manual and door sticker, I've basically achieved their quoted figures. So what does this prove? Well for one it proves that tyre pressure is absolutely linked to your car's economy. I can get an extra 50 miles between fill-ups now. It also proves that it's worth researching things if you think something is a little odd. It does also add weight to the above motto about not trusting forecourt pressure gauges. Imagine if you're underfilling your tyres because of a dodgy pressure gauge - not only is it dangerous, but it's costing you at the pump too. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted March 2, 2005 Share Posted March 2, 2005 You can buy a universal type here, and get the split deepwell socket too. http://www.oxygensensors.com/ It should improve your mileage tho! Quote Link to comment Share on other sites More sharing options...
86subaru Posted March 2, 2005 Share Posted March 2, 2005 i have the same thing going on ,on mine, where do you get your gas at ? same place all the time or cheapest place ? i have heard that ky has very cheap gas, some board members will say there is no difference in gas ,but there is , aleast around here , also remember you are warming up your car since it is cold out , , but the other suggestions are true also Quote Link to comment Share on other sites More sharing options...
subie94 Posted March 2, 2005 Share Posted March 2, 2005 how exactly do you figure out mpg? i'm not really worried but was curious. Quote Link to comment Share on other sites More sharing options...
jamal Posted March 2, 2005 Share Posted March 2, 2005 Miles/gallons. Reset your tripmeter when you fill up, then the next time you get gas, divide the miles you've traveled by the gallons you put in. I have a gas gauge that isn't very accurate, so I need to keep pretty good track of my mileage and how far I travel on a tank. Quote Link to comment Share on other sites More sharing options...
frag Posted March 2, 2005 Share Posted March 2, 2005 Trying to answer two questions asked in this thread about O2 sensors. 1) How does one know he needs a new one if there is no CEL code to that effect? Here's how I do it (it's just me) a) I check for unusual soot build up in the tail pipe, sign of an overly rich running engine. You have to know how "usual" looks in order to use that as a clue. If it has'nt been replaced for the last 100,000 miles c) Using my Harrison's OBDScan tool ( software for the Palm computer) that gives real time output of all the sensors. The O2 sensor voltage output must flutuate rapidly between 0.1 and 0.9 volt and must cross 0.5 volt at least 5 times in 10 seconds. 2) How easy is it to replace? In my case (2.2 L engine and MT) I just bend over the right fender and go at it with an open wrench. The sensor is just under and behind the right inner cv joint boot. My 2 cents. Quote Link to comment Share on other sites More sharing options...
subie94 Posted March 2, 2005 Share Posted March 2, 2005 Miles/gallons. Reset your tripmeter when you fill up, then the next time you get gas, divide the miles you've traveled by the gallons you put in. I have a gas gauge that isn't very accurate, so I need to keep pretty good track of my mileage and how far I travel on a tank. thanks for the info/gonna try it next time i fill up,my luck i'm probable gonna have low mpg cuz of the way i drive:brow: Quote Link to comment Share on other sites More sharing options...
RubasuGirl Posted March 2, 2005 Share Posted March 2, 2005 Ok, I'm going to go on a different slant. Maybe I missed something, but I'm going to go for the obvious: When is the last time you did a tune-up on your car? And by a "tune-up", I mean have a Fuel Injection/Carbon Removal done (I don't mean the stuff you just put in the gas tank. I mean the real thing - some use SeaFoam, others use other stuff), replace the air filter, fuel filter, spark plugs, etc. I notice a HUGE difference in performance of my car and I perform these things every 30k miles. I notice a difference in Gas mileage too.... not 5mpg, but 2 or so. And I second the comment earlier (sorry, I forgot who)... be careful where you get your gas from. Had a friend that told me to only put XX gas in my car. I did... and complained about the gas mileage. Then, out of desperation, I had to fill up somewhere else. Whoa. Made a huge difference. Also, a couple of times, again, out of desperation, I had to fill up at the "discount" places, ick. Horrible gas mileage. Noticed a 4-5mpg difference. Sorry for the rant, but I would check to see when the last service was done, and how intensive. Just my two cents. Quote Link to comment Share on other sites More sharing options...
LosDiosDeVerde86 Posted March 2, 2005 Share Posted March 2, 2005 Anybody else had to deal with the poor mpg gremlin in the Sube? Any tips/ideas? I love my Legacy, but I cannot drive a 20 mpg car... my 96 legacy LS 2.2 gets 17mpg. whatever. Quote Link to comment Share on other sites More sharing options...
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