Has anyone had their mpg system break? I don't know a better word for it, but basically, my mpg shot up across the board, by like, a lot. All I did was mess around with the sport mode for a bit and take the sun roof deflector off (best thing ever, so much quieter).

I know technically the deflector being off should increase mpg, but I thought it wouldn't be noticable, and even if it did, it would be negligible. Only mentioning because maybe gas mileage actually went up some because of it.

Keep in mind, I can say with a FACT that me messing around in sport mode (for a very, very short time) was the first time that car has ever been in sport mode, the previous owner was an elderly lady. Maybe that flushed out some lines or something? I have no clue how cars work!

So tonight I did a "formal test" and drove 15 miles, one on highway one not, in a downtown metropolitan. Got stuck in traffic for a little bit, of course, but the results were astounding. Previous drive was highway, and the "current" drive was through downtown, where I chased around a classic car to tell him I liked it 😂


If it's not some weird mechanical thing, and could actually potentially be a fault, can someone explain to me a good system on how to track and cross reference gas mileage to actual gas mileage? This was my first car, never even had to think about doing that before 😂

 

I know on the (at least my) GE8 Fit the fuel efficiency calculator on the dash is unreliable. Some tanks it's high, some tanks it's low. Usually it's within about 2 mpg of truth, or at least the best truth that you can easily calculate, but I haven't been able to identify a pattern in the direction of the error vs the driving I did on that tank. Hopefully someone with a newer Fit like yours can respond with GK5-specific information.

If you really care about tracking your fuel efficiency, you need to calculate at the pump. If you're a bit OCD and your driving allows, you can try to fill up at the same station and same pump for each tank. Your best estimate of fuel efficiency is obviously the miles you've driven divided by the fuel you used. Over multiple tanks you'll be able to determine if the values reported on your dash are accurate.

If you're extremely OCD, you might also use a GPS or the highway mile markers to determine the accuracy of your odometer. Even if your car left the factory with a perfectly accurate odometer (unlikely), if you've changed tire size or if your tires are nearly worn out (and therefore rotating more times over a given distance), your odometer will be a bit off from reality.

For me, letting the fuel pump go until the "click" and calculating the miles driven from my odometer, which is pretty close based on comparison with a GPS, is good enough to tell me how I'm doing.

 

you really have to go by the miliage you're getting per tankfull . i zero out my " b " milage display with every new fill up . i don't touch the " a " display , that tells me a more accurate MPG
average . also , the gas now is the winter formula , has less energy . my Fit's mpg has dropped 2 -3 mpg