2003 5AT.

A lot of my drives are short 0.8 mile drives to campus and back, usually hitting plenty of traffic lights along the way, but 12.5mpg? really? I even try to drive conservatively. Should it really be this low? Even when I mix in a few drives that are like 3 miles there, 3 miles back, my gas mileage doesn't really go up. This car doesn't get a lot of highway mileage anymore, as I'm in a college town. Dealer said everything on the car looks fine (air ratios and whatnot) It is cold here right now (30 degrees)

 

Are you calculating your MPG with the digital gauge or miles per tank?

 

This is normal considering you drive such a short distance and it's all city driving. Your car never really gets a chance to get up to normal operating temperature and the cold weather isn't helping either. Gasoline doesn't atomize and burn as well with cold weather.

 

Just using the digital gauge.

Should I let my car idle to warm up before driving off? If so for how long?

 

Maybe your knock sensor is shot?

I know this is a pretty common problem on the VQ maxima motors, they stop working but dont throw a code.

less than 13mpg is crazy...something is def not right

 

I read somewhere that the digital gauge on our Z's take idle time into account so it shouldn't be used as an accurate measurement (correct me if I'm wrong). I use my Garmin 80% of the time while I'm driving, and it says that my average MPG is about 15.5, and I too mostly commute about 2 miles a day along with some highway driving here and there.

In comparison, I reset my gauge frequently to see what it says. I've gotten anything from 12-15, and currently it's at 12, whereas my Garmin says I'm at 15. I usually let my car warm up until the needle goes below 1000rpm.

 

Fill up your tank, reset your trip meter, drive until the fuel low light illuminates, record the miles, fill it up again. Divide the number of miles you drove by the number of gallons you put in on the 2nd fill up.

 

This.

 

Calculating it manually is the only true way to tell

 

Because racecar

Short drives will always = poor fuel economy

 

Im barely getting 15mpg sad i know.

 

Short drives always give me really bad mileage. 11 or 12 mpg. The one time I had an issue was when my RPM's when driving were around 3000 to 3500 RPM. I drive an automatic. I was told to disconnected the battery and that it would reset the RPM's to the way they should be. It worked and one pep boy guy said that the cold might have been a factor.

Other than that if you have mods or a dirty air filter that might be reducing your MPG. But best way to tell is fill it up, drive until empty and fill it up again them take the miles driven divided my the gallons of gas you put in.

Also take into account that the gas gauge has issues so it shows empty even when you have 1/4 worth of gas in the tank.

Good luck, I know was in my area is $4.27 so low MPG sucks right now.

 

Yeah with the digital gauge you can sit there idle for a few minutes then when you drive off it'll register really low mpg. Basically you were using gas but not going anywhere lol...

but I wouldnt trust the digital gauge if your driving short distances. I only use it on the highway during long trips. If i go a couple of months without resetting it and driving around town it will say anywhere from 18-19 to 20-22... highway from 25-29 depending on speed. I tried it on the highway today and at 72 mph it was averaging 27mpg...

 

I do that too, now from time to time. I reset the mpg gauge every time i fill up , the most it has been off is 0.4 and it is usually 0.2 off.

12.5 average with a 3 mile stop and go traffic, even a prius would get crappy mpg

 

This is true.

 

I also live a half mile away from campus. When I reset and just do the small commute, my MPG will calculate as low as ~11. I tried resetting when I was driving several miles on a 45MPH road; with little stoplights I got as high as 23.1MPG.
Next time you are going to make a run on the freeway (or anything not just a mile away), try resetting and you'll notice a way higher MPG.

 

This. I've done this to get an accurate reading a few times. My gauge read ~9mpg once. As someone said it takes idle time into the calculation so its not 100%.

 

17.8 mpg here.....

 

I refresh the MPG thing in our Z to see what I get every tank when I fill up...

Im ALWAYS in the 20 mpg in my HR-Z.

20.2 to 21.8 is where I range from and I race and drive the **** out of my Z. Its what you do when you're not beating on it imo.

drive easy.. you can still get on it a lot and get good gas milage though.

 

It always takes idle time into the calc, even if you do it manuelly. If you drive 19 miles while getting 23 MPG, then let your car idle till you burn off 18.2 gallons, fill up which will be 19 gallons then calculate it will be 1 MPG. Any time an engine is running, it will factor into your average MPG. The average MPG is what you get by manuelly calculating or by reseting the MPG gauge when you fill the car up.


Since we don't have a real time reading, the gauge reset while (steady state)driving can give you an idea. My Juke has real time, even with the cruise control set, it is all over the place.