Hey, just wondering, tc's have a 14 gallon tank, so...approx how many miles do you guys put on a tank because mine is pretty bad and i dont know why, or is it normal, the max i've got so far is 186 miles on a whole tank, so idk whats goin on. Please help me out lol because it seems sorta low

 

how's your driving habits?...

i used to get just over 300 miles on my old 13gal. 1.6L 94 sentra (mainly suburb driving no city/hwy). my 1.8L matrix gets a good 260 miles on a 13 gal tank, and i get a good 320+ on the hwy. both auto. amazing how mpg can vary so much.

 

Yeah, thats not normal. Is the car a manual or auto? Any mods? What are the tire pressures? I keep mine at 34psi. Air filter and spark plugs in good shape? Could also be either a lead foot or an issue with an O2 sensor or bad ECU. Whats your MPG on the highway? I get about 27mpg highway/city driving 31mpg highway.

 

Actually it has 14.5 gallon tank and that is indeed not normal, I at least hit 200's on a bad tank when my driving is aggressive, and hit 300's driving to conserve.

 

Mine is Automatic, i have a TRD Intake, Air Pressure im not sure about due to the fact that i have 19's with low profile tires (have a flat spot on one of them), As for the air filter and sparkplugs i have no clue to be perfectly honest with you, spark plugs i havent checked, air filter i have an intake. Whats lead foot? as for my O2 sensor, not quite sure what that is or what it does, how can i check//fix it? and same goes for ECU, how can i check//fix it? As for MPG on highway i have no idea, because im on and off the highway and mostly streets. My TC is an 05

 

How many miles does your Tc have total? Not sure about this car but they say with my old 328i to change the O2 sensor out every 100k miles. Id just check the simple things for now, tire pressures (check sidewall of tire for max cold pressure), check the air filter, fill up the tank and zero out your tripometer. Find a near by highway and try and stay the speed limit, try not to do this when its rush hour traffic. Go about 10-20 miles than fill back up and find your mpg (mileage done/gallons of gas filled to top off tank = mpg). Should have a mpg roughly 28-32 mpg. Lead foot means you floor the gas peddal everywhere you go. If its still horrible on gas take it to the scion dealer and they will have to hook up a computer to your car to see whats going on. Oh and an O2 sensor tells the ECU, gives the fuel mapping for your engine, if your engine is running rich or lean. If the O2 sensor goes bad it usually gives a check engine light and your fuel mileage goes way way down.

 

ye i do floor the car alot, thats just the way i drive, but the thing is i tried to drive normal one time when i filled up just to see if the car gets better milage, and it got 158 and when i floored it none stop i got 186 so yea, as for milage on the car, it has 31,500 around there, i dont have an air filter, i have an intake, and ill just have to check that filter if its starting to get clogged up, and how much would an O2 sensor change be approx?

 

With that low a milage i doubt its the O2 sensor. You still have the powertrain warranty right? Take it in and say its getting bad mileage. Try and put the stock intake back on though if you still got the warranty. I think a few people have had bad ECU though, not sure what it costs but im sure its not cheap.

 

Damn I'm Lucky if I can go 7 days with the same Tank. I checked Friday that I filled it up and I had about 250 Miles. Today's sunday and I only have half a tank but with 150 miles on it.

Any parts that will help my mileage? (I have an AEM CAI already)

 

There are already a few posts on improving gas mileage. Seems that the best things are higher than listed tire pressures, mine are at 34psi, and being conservative with gas peddal, shifting below 3k/coasting to a stop etc. You can also be more daring and add acetone to your gas but some say it does not work plus you increase the chance of messing up your fuel lines.

 

how do you know you are getting 186 miles? If you are just measuring to when you think you should fill up, you could have 40 or more miles in the tank. You fill it up, record the mileage, drive it till you want to fill it up again and see how many gallons it takes. Divide that by the mileage between the two fillups and you get the mileage for that tank. If you fill it up when the gas light comes on you have at least 40 more miles in it most times.

And 99% of things you purchase do nothing for mileage.. and the 1% that do cost more than you will recover in fuel savings. Other than driving habits and maybe adding a bit of air to the tires (VERY small impact) it isnt worth it to try to mod the car to get better mileage. In that case you should have read the window sticker and decided to buy a more economical car

 

Your biggest problems against fuel mileage: 1) flooring it a lot. 2) running on 19s - which are probably a lot heavier than the OEM wheels.

Heavy wheels means more mass to start moving and keep moving, so you're going to use more gas doing so.

But like engifineer said, saying you get 186 miles out of a "14 gal tank" isn't exactly accurate. You need to fill your tank, reset your trip mileage at that very moment and then drive until you need to fill up again. Fill the tank up - write down the mileage from the trip (and the gallons used to fill up) and then reset it again. Use those two numbers you wrote down to calculate your actual mileage.

 

I'm sure those ginormous 19" rims don't help the gas mileage any...but are you sure you're calculating those figures correctly? I can't imagine how your car gets THAT bad gas mileage.

Do what engifineer said then let us know.

 

When you guys are on an empty tank (the light is lit) and you decide to go fill a full tank, how many gallons are you able to get in? I think I've barely gotten 13 gallons in once, but most of the time its high 11's to high 12's (gallons).

Does that mean I still have a gallon or two left in the tank?

 

The light typically comes on when there is about 2 to 2.5 gallons left. That's b/c the light isn't to say you're out. It's saying that you should refuel soon. You should be able to usually get another 40-50 miles once the light comes on.

So yes, 11-12 gallons when the light comes on is normal.

 

There is a flip side to heavier/larger wheels though. Any spinning disc acts as a flywheel, meaning it stores energy rather than dissipating it (for the most part.. rolling friction has some play in it as well). So once you get that heavier wheel to speed, it is easier to keep it spinning due to it having a higher moment of inertia. This is part of the reason a car is more efficient at cruising speed than it is when stopping and going all the time. So some of the detriments of weight are cancelled out in the efficiency area. Now, a larger overall diameter is also bad, so if you increase overall diameter by 10% lets say, the engine has to produce 10% more tq at the axle to apply the same amount of force to the ground. But for the most part, people running 19" inch or smaller rims are running at least a lower profile, which keeps the change on diameter fairly low.

 

the few times the light has some on for me i only got 11.x gallons in the tank, yes that means you still have 2-3 gallons left...

im running 19s also and i get around 20mpg with a fairly heavy foot, but i have a lot of other productive and much more counterproductive mods also...

 

Alright, well i know 19's dont help, but either way i dont think my milage would be THAT bad just becuase of that. as for all the other stuff mentioned, ye i do floor it alot lol thats just the way i drive due to the fact of where i live because alot of idiots are on the roads and i have a short patients span lol. everytime i fill up i always reset the trip. just to see how much i get, when the light comes on i drive for another maybe 20 miles just to be on the safe side becasue im scared of getting stuck you know, usually i end up putting 13.5 in the tank which runs me a good 40-45 bucks, but the most ive gotten is 186 from the trip. when i filled up. like right now for example my milage is horrible, i filled up on friday, and today is sunday, i put 120 miles on it roughly, and i have a quarter of a tank left, thats just simply horrible, even with my flooring and 19's, it cant be that bad, at least i think it cant, i mean its a v4 for cryin out loud you know. and as for me thinking of gettin a more gas saving car lol i already have a prius which is my moms, but that car is slow, and very uncomfortable so hence i bought this one, and i got a great deal on it, i bought it with everything in, indash, rims, intake, remote started, body kit, sports package basically on the car along with a bunch of other stuff, its 2005, with 30K miles on it, for $14,700, which i found to be good, its mica color, and automatic (dont know how to drive stick) so i ended up getting it cuz i loved it, but still this gas milage problem is ____in me off, what else can it be, im going tomorrow for an oil change, going to check tire pressure, but other than that i mean idk what it can be, i put regular in it, since thats what it says to do, but i dont think that would kill milage, i think that would only give me better milage...

 

how bout easing it up on the foot this time around. and if you have the money, get a scan gauge if your concerned about mileage. it doeasn't help for mileage but good if you like to keep track on how much gas ur eating up.

but anyways...if your not flooring it this time around and your mileage doesnt increase. it should be checked out by the dealer/shop.

 

since you say ur driving an auto, is your overdrive off? having it off will decrease your mileage significantly.