There is only ONE simple way to determine MPG at the consumer level:

Trying to "guess" using the gas gauge or how many miles did I get on this thank is only a WAG if you don't use the actual miles travelled divided by actual gallons used - real numbers!

Example:

 

87 octane. However, that is what the dealership put in. I wouldn't be to concerned if it was a few miles different, however, 80 miles? That as a huge drop.

 

dont know how ya'all are getting 340 miles on a tank of gas, ive hit 300 only once
i have an '04 5spd, K&N air filter, stock whls, TRD springs, stock exhuast, TRD shifter
drive it like i stole it most days, cruise at 70-80mph and i get 27-29mpg consistantly no matter how hard i drive. i have notices with stock wheels to engine revs a bit around 4k rpm at 80MPH, i can suck down sum gas cruisin at 85-95mph.
really was a bummer driving down I-5 to SoCal, car wants to do 100mph but the gas guage falls like a V8 is under the hood.......

 

dont know how ya'all are getting 340 miles on a tank of gas, ive hit 300 only once
i have an '04 5spd, K&N air filter, stock whls, TRD springs, stock exhuast, TRD shifter
drive it like i stole it most days, cruise at 70-80mph and i get 27-29mpg consistantly no matter how hard i drive. i have notices with stock wheels to engine revs a bit around 4k rpm at 80MPH, i can suck down sum gas cruisin at 85-95mph.
really was a bummer driving down I-5 to SoCal, car wants to do 100mph but the gas guage falls like a V8 is under the hood.......

 

Has anyone put together information about gas mileage, comparing different locations in the US . Like comparing Denver to Daytona Beach. Different altitudes and flat or hilly terrain would have a big effect on mileage. As well as speed driven Here in southeast Tenn. the terrain I drive is slightly hilly Altitude is about 1000ft. I have a RS 2.0 with automatic. On the interstate I drive 70-75 and speed limit everywhere else. I drive 70 miles round trip to work and have to slow down to go through 2 towns. I am averageing 33 to 34 mpg. When I fillup, I always use a pump where my car is slightly higher on the drivers side and fill it till gas is standing in the filler neck. This way I know I am getting the tank as completely full as possible. And it cuts down on any possible error in computing my mileage. I have 4100 mile on my box, and I drive with a sane foot.

 

I have never seen above 35...and below 29

 

Isn't that what I wrote? mileage drive / gallons pumped = MPG

 

Yup, that's what you wrote, eggie. We were both saying the same thing. It's just that some folks either can't hear or don't listen.

I still see the "I only got 100 miles on half a tank of gas!" type posts where the people are using their gas gauge to determine MPG, and that just DOES NOT work. *sigh*

As we both said, eggie, you have to use the real numbers to come up with a real answer, not "I went xxx miles before the yellow light came on."

 

Second tank was 33.09 mpg ... going to interesting in the next couple of weeks as my new 15' Rota's and 205\55\15 BFG GForce Sports should be on by next friday. Expecting a hit in MPG mostly from the width increase. Overall wheel\tire weight should be a tad lighter than stock....lighter wheel but heavier tire and I know heavier tire is going to hurt. Interesting comparing tire weights in this size...they went from 18lbs all the way to 23lbs. Kumho does the lightest but no dealer in my small town....Gforce comes in at 20lbs.

 

Welp, this sucks.... I just drove to San Jose and got 174.9 miles and used 7.4 gallons giving me 23 F'n miles per gallon!!!! Maybe it had to do with windows half down doing 75?

I decided once here in San Jose to reset my ECU and see if that matters. I'll report my mileage home.

 

YOU DRIVE A BOX. NOT REALLY AERODYNAMIC.

 

:D

 

One of the better license plate frames I've seen was on the back of a Honda Element.
It said "SCREW AERODYNAMICS"....

 

Yes, I know I drive a box and the aerodynamics is out the window on design, but 23 is a super far cry from advertised 31 "CITY". I was "HIGHWAY" all the way.

I'm pretty sure it was the window thing. I filled up in Salinas and drove to San Jose. 50 miles +/-. Reset ECU. Drove top Gilroy for dinner, another 50 +/- round trip. Filled up again for the trip home and put in 3 gallons. That is roughly 30+. the exact is unknown because I reset everything by pulling a battery cable for 10-15 minutes.

 

Here's mine:

Model Year: 2005
Transmission type: Manual
Rims: FACTORY ALLOY
Engine Mods: NONE
Transmission Mods: NONE
Suspension Mods: NONE
Avg Speed: 65-75
AVG MPG: 32
.....AZ slow speeds...

 

Ok just got back and these are my results:
65-75
AC "ON"
Windows "UP"
195 miles / 6.4 pumped = 30MPG

Bout time. I'm thinking it has to do with driving with the windows down. My buddy said it like this, "Driving with a parachute open." All the wind coming in and slamming that back window doesn't help.

Anyways, I'm sure if I drove without the AC on I'd get better, but I'm happy I broke into the 30's atleast.

 

Ive got just over 30K miles on my box...still averaging about 32-33mpg...just odnt beat on it and youll be fine

 

Just in case anyone missed this:

https://www.scionlife.com/forums/vie...246&highlight=

The EPA is changng the way it tests to increase accuracy...

 

It is normal to get less mpg's when an engine is new. But that isn't a very common situation with modern engines. Modern engines are pretty much broken in when shipped. Mpg's will vary under all conditions such as speed, weather, traffic, terrain, temperature, weight in vehicle, etc, etc. The milage that was posted on the window sticker was the mileage gotten during a run on a test track that has set variables and driven with set parameters. This is not the mpg's that You will get. And it's not the mpg's that any vehicle will get when used by "Joe public" on public roads. It is only meant to be used as a comparison figure when comparing vehicles gas milage. So don't hold it against Scion. They are mandated to print those figures by the Feds. Your new intake and exhast may help a little with mpg's but don't expect much if any. Changing the wheel size will not affect mpg's as long as the "rolling radius" isn't changed from stock. Lowering the "rolling radius" will have the same effect as raising the differential gear ratio. It will also hurt mpg's but will boost Your towing ability <G>. Increasing Your "rolling radius" may help mpg's but will hurt performance. It may also cause premature drive train wear as the engine will be "lugging" to get up to speed.

 

I have been averaging 27 mpg city/highway combined since I bought my car.I just turned 3000 miles today and it is still the same.
Rarely go over 65
aem intake
dc sport header
trd muffler
17" chrome wheels
215/45's