loss of gas mileage

[annie_vernon]

i have a 2003 pontiac vibe and its been great. i have kept up on the oil changes and regular maintenance. but sometimes (particularly, now) i have had a down turn in the amount of gas i have been able to get per gallon. specifically, half a tank, its at about 150 miles, which is way below average. what kinds of problems can arise from a harsh winter in illinois? i havent been driving exceedingly fast, and all levels are normal

[star_deceiver]

Do you have winter tires? Do you take many short trips or drive like a bat outta hell when taking off from lights? How long have you owned the car for? Do you let it idle for a while to warm it up?When (if ever) were the spark plugs replaced? Fuel injector cleaner ever used?

[keithvibe]

so many issue can cause thisfirsthow many miles?has this been happening over several tanks of gas?Are you using snow tires?things to check and resolveclean the mafcheck tire pressurechange the air filter if your still using the paper versioncould need a tune upcould be the winter blend of gas that is causing your issue.

[annie_vernon]

i do (sometimes) drive like a bat outta hell but not on short trips. i have all season tires. theres no snow on the roads here. i have less than 100,000 on the car, i bought it used in may. this has just started happening. whats a maf? will check tire pressure. the air filter was changed about 5,000 miles ago. i hate car problems.

[annie_vernon]

oh and i start it and go. no idle. and no fuel injector cleaner has been used. what is that? is it beneficial?

[keithvibe]

this is the maf sensor.You will find it located in the air intake tube.it might need some cleaning at 100k you should have a tune up done.in fact a lot of things should be done/checked. lolgas treatmentAdd it in when your gas tank is almost empty.Run the full tank of gas.

[annie_vernon]

hey thanks thats a huge help. this is a lot to ask i know, but could you give me a prioritized list of things i need to get done as i hit 100,000 miles? this is my only car, and im on a very fixed income(i work at a non-profit) and i would hate to eff up my lovely car. i know general stuff but...

[keithvibe]

Quote, originally posted by annie_vernon »hey thanks thats a huge help. this is a lot to ask i know, but could you give me a prioritized list of things i need to get done as i hit 100,000 miles? this is my only car, and im on a very fixed income(i work at a non-profit) and i would hate to eff up my lovely car. i know general stuff but...start with the fuel system cleaner.You can even do two treatmentsone bottle at a time in one tank at a time, of course.then have someone clean the maf, if you are comfortable doing some work yourself it's pritty easy to do. If you need a step by step let me know.change the plugs and wires.if your trans fluid hasn't been changed yet, it should be. If you car is an awd the front and rear diff(s) fluid should be changed.If it's a 5 speed keep in mind if the clutch hasn't been replaced, yet your getting to the "need to change the clutch" time frame.

[annie_vernon]

ok great. i have an auto. this is what i know was changed. the trans fluid was done at 70,000 and brakes were done and then, i had them resurfaced in september. i want to do some of the easier stuff myself. the purple stuff, in the reservoir near the front, (i sound like a doof) anti freeze? that was just done in may before i bought the car. i dont know when the brake fluid was done. should i do everything but the trans fluid? at my next iold change?

[star_deceiver]

Replace the spark plugs and clean the MAF sensor!Is the brake fluid clear? If it looks like coffee ground water soup then I would have that flushed. The antifreeze should be a pinkish orange, as your car's 8 years old now it should have already been changed, but check it with the antifreeze tester anyways.Purple stuff??? I know walmart used to sell purple windshield washer fluid...Bad mileage in winter is also caused by the winter blend of gasoline used in colder states. I know my mileage goes down every winter!

[joatmon]

first of all, welcome to genvibemy gas mileage always drops in the winter. Hard to know if the drop you are seeing is normal, or a sign of something needing maintenance. Also. keep in mind that one tank of gas taken individually is not a good indication, becuase it depends a lot on how full you filled up, which will vary each time no matter how careful and methodical you are. The mass air flow (MAF) sensor monitors how much air is passing though the air intake, affects fuel/air mixture, and can have an effect on fuel economy. THey are not cheap though, so some care iis needed when cleaning them.The fuel injector cleaner is really easy, and not that expensive, so that's a good thing to try. As others have already said, the spark plugs, if original, probably need to be replaced. There are no spark plug wires to replace, so if you take it to someone to have the plugs replaced, don't let them tell you they replaced the plug wires. And too low tire pressure can kill mpgs, as can poor alignment. viewtopic.php?f=17&t=6088&#p65128 has an excerpt from a factory service manual on what to check if fuel economy is low, many of the things there are involved. Definitely start with the easy stuff first, and since this is your first winter with the car, it's really hard to know if the drop is typical winter drop or a sign of some repairable problem.If you do not have a copy of the owner's manual, you can download a PDF of it from http://forums.genvibe.com/zerothread?id=1010 In the 2005 Vibe owners manual there, page 5-12 has a picture of the engine compartment. In that picture, "A" is the windshield washer tank, "E" is the coolant overflow tank. Let us know which of those has the purple stuff in it.

[keithvibe]

sorry Joatman is correct I just have a bad habit of typing plugs and wires... Kinda like when someone asks for peanutbutter and jelly .... hard to say one with out the other. lol

[beemerphile1]

Quote, originally posted by annie_vernon »i have had a down turn in the amount of gas i have been able to get per gallon... Unusual, I'm still able to get the same amount of gas per gallon. Maybe the pump is reading incorrectly. Okay, I'm just messing with you.My fuel mileage is always bad in the winter. Short trips in cold weather means that the car is almost always operating in a fuel rich condition. If you regularly make longer trips the difference is not as bad, but if most of your driving is short trips the mileage drops drastically. Probably just normal.

[joatmon]

I hadn't noticed if you said plug wires, I just remember someone saying they got lied to and billed by a shop for plug wire replacement on a Vibe. Just a heads up to anyone that takes the car into a shop for a tune up. The coil on plug things in Vibes can go bad, but so far it is an uncommon failure.

[JetBlack09VibeGT]

There is one thing that we are all missing here, except for Star Deciever, I think he was on track... Annie_Vernon said she lives in Illinois. Since many Midwest States switch to a winter blend of fuel, or oxygenated gas, we end up with a significant dip in fuel economy. The purpose for the winter blend is to reduce the CO2 emissions that are typically higher in engines running in colder climates. The biggest drawback of using Oxygenated Fuels is its reduced energy density resulting in increased fuel consumption.I see an average of a 25% swing in fuel consumption from summer driving to winter driving, of course snow tires don't help but even before I used snowies I saw a 15-20% drop.

[hipeman]

I hope the "winter blend gas" is the issue. I just bought my '06 Vibe two weeks ago. One reason I bought it was the 34+ mpg. 95% of my driving is back & forth to work 60 miles a day with all but 2-3 miles driven on the highway. I set the cruise to 70mph on the highway, and drive almost grandpa-ish in town if you ask my wife. So far on my first two fillups I'm got 26.9 & 26.7. Definitely not what I was expecting. I live in Michigan so I've got all weather tires, properly inflated. not sure about when the last tune up was, but I'll try the fuel treatment next fillup. and check out the MAF sensor when I get a chance.Thanks for the tips!

[torque2k]

Hey, a fellow GR native! I'm on the north side of Lowell, so I do that 25 mile run twice a day, down M-21 to 96/196 into downtown. I have a 2003 AWD, and my mileage has NEVER been what the sticker said. In the winter, with the stop/start driving I do, I get about 24MPG in the winter, and about 27MPG in the summer. Yours seems a bit low; are you rockin' an AWD, or base or GT?Keep in mind, we've got crappy roads around here, so if you're struts are starting to soften up (as mine are), you're going to get worse mileage from not having the tires flat on pavement 100% of the time, and your tires will wear quicker. That's going to happen even at "grandpa-ish" speeds. Also, our weather has really been hard on cars this year, what with the extreme drops, then the January thaw, then the humidity as we sit around 32-36F... and we run on winter blend until about May. It's hard on our little engines. I notice worse MPGs when it's humid like it's been this week so far.Personally, my car has been dogging lately, but I think many of the above points to check need to be done on mine, as I'm hitting 110K soon and haven't done much upkeep on it.

[NJVibe04Salsa]

150 miles is pretty bad. I just posted a message on another thread about how I fixed the mileage on mine. There's a known problem with a gasket in some engines.http://forums.genvibe.com/zerothread?id=36614scroll down to the bottom.

[cptnsolo77]

150 about half tank? Thats what I have been getting with my Vibe since I bought it at 38K, now at 100K. I have a drop in K&N, cleaned the MAF, throttle body, & PCV valve. Tires are @ 37 PSI all around. I avg 27-28 MPG highway/city.....& im very easy on the car. My mpg is closer to 30 when its stricktly highway though. I did everything I know to help. Mileage hasnt been any better or worse...lol.

[NJVibe04Salsa]

oh, I skimmed through and thought it was 150 per tank. At one point before the repair I was getting under 200 for a full tank.