Hi, I was flipping through the digital guage (to the right of the steering wheel) and I found the gas mileage.. It was reading 2.9 MPG!! I have a 2003 Roadster with stock engine (3.5L V6) This cant be right. can it? Gas drains pretty quickly with aggressive driving, but it cant really be this low..

 

You're kidding, right? How fast were you moving? The MPG reading is tied to how fast you are driving at that point in time.

 

No...seriously, I was probably doing 45 in a 30.. Nothing to fast.. Constant speed with the occasional rev.. But that cant be right...Possibly something wrong with the guage?

 

So how many miles are you getting to a tank? 45?

 

reset it, it will go to low double figures if you nail it, but i usually get around 25mpg for normal driving.

have you done a lot of stop start driving, ie moving it a few hundred yards when engine cold etc?

it is an average since the last time you reset it (UK spec) and not an actual at-that-point-in-time reading.

 

I will try reseting it..but as bad as it sounds, I think it might be right. (or close to) I drove around town for about an hour and it dropped about 3/5 of a tank. Im still in shock though, cause that doesnt seem even close to being right. My 04 Lincoln Navigator gets 11 MPG...thats a big V8 too..

 

I know if you reset the gauge and then sit at a light for five minutes you can get a number like that but I don't know any other way. The worst I have seen after normal driving is 15mpg.

Chris

 

Mine hang around 12.5 but my average speed is just 19 mph.

I drive city traffic and that's the average for my 4 mile commute through +15 stop lights.

 

I never get above 14.7 mpg. Don't think I drive hard all the time so I don't understand why it's so low.

 

I get around 14 mpg according to the gauge. I fill up about 2-3 times a week, I drive the car like I stole it though....

 

meh...I take that gauge readout with a big grain of salt. I'd say pick your favorite gas station and favorite pump and fill the tank up. Record your odometer reading. Drive around for the next few days (or hours, in your case) as you normally would, then go back to the same gas station / same pump and fill all the way up again. (Only fill until the pump cuts itself off). Again record your odometer reading, and record how much gas you had to put in to fill. Repeat a few more times. Then use the recorded data to get your average mpg, and see how it compares to the digital readout. If you calculate 3 mpg by hand, then I'm afraid it's time to visit the dealership.

P.S. - Not trying to be condescending by teaching you how to track gas mileage, because I'm sure you knew it already, but I'm just stating that I put more faith in hand calculations than a little gimmick gauge. If anything, I use that gauge to monitor fluctuations in fuel efficiency, not the actual fuel efficiency reading.

Good luck man!
-Steve

 

24 & 18 here

 

24 by hand calcs here and always 20.8 or 20.9 by gauge

 

If you have an automatic, yes, for manuals it depends on speed & gear. 30mph in first will give drastically lower mpg than 30mph in sixth.

I get ~17-18(12-15 if I romp) in town and have rated up to 28.8 on the highway.

If this is the first you've seen it, I suspect it had probably been run for a while, but not really moved very far, say like at the docks or something, waiting to be loaded on to a truck.

 

23 by gauge and 22 by hand calc, but mine is still new(1 month)

that gauge does not seem right though, you would have to be haulin a$$ everywhere...and then you would still get like 19 or 20

 

im getting 29 or 30 mpg. way better than my honda did

 

I get 20 for city driving and 21.6 for highway.

 

I have about 20k on my Z and I reset my gauge after every fuel up. I average between 18 and 22. Although If I hop on the freeway right after filling up I can get as high as 40-50mpg. I drive my z pretty hard and I have never seen it lower than 14mpg. I am really suprised by all the mixed numbers.

 

I agree that the gauge is off. Mine once told me I avg. 30mpg and I couldn't belive it. So I did my own calculations and found that on average, the gauge is off by about 5 mpg.

 

You can only do your own numbers based on a full tank scenario, or top off after you know you have a full tank, and then it's always going to be slightly off because you can never know exactly how much fuel has been used, or the given time and distance.

Where as the vehicle does know exactly how much fuel has been used in relation to an exact amount of time and distance. I would trust the gauge numbers over mine anyday, for just that reason.

For example, NASCAR's don't have fuel gauges, everything is done by hand, but, and this is a BIG but, they know accurately how much fuel they are consuming, because they know their times/distances and exactly how much fuel was put in the car prior to the race, and even go so far as weighing half used fuel cans to determine just how much fuel has been replenished in the vehicle during a pitstop. Then you get a caution, and all the numbers are thrown out the window, because the consumptions change.