I calculate mine using the manual method as the display is consistently off by about 2 to 2.5mpg.

 

Me too, but I keep track of both. It is hard to take pictures of calculations but the display is very photogenic.

 

Same here. I calculate, but keep track of both. Through 5 tanks, my dash has been 0.7 to 1.8mpg low.

 

yeah the computer forgets to factor in when you park your car and its cooking under the sun while the gasoline vapors escapes, lowering your gas mileage. Some systems have a vapor recovery system where some of can be used instead of wasting it all into the atmosphere.

so hand calculation is what I look forward to, just get a recept and write the number of miles on it. Then enter it in the databases when one gets home.

 

I think all hybrids have vapor recovery systems. For that mater I think all newer cars have vapor recovery systems. I don't think much escapes if any.

 

In my limited (5800 miles and 1 roadtrip) experience, the trip computer is more accurate for long drives w/in a tank than lots of short ones. Long distant trips register w/in a tenth or so per tank, but the dozens of little regular trip w/in a tank are usually lower by 2-4 mpg than manual calcs at fillup. It also seems that wide swings in average over a tankful can be misrepresented as well. For instance, you start off in low to mid 40mpg range over the first 100 miles, and slowly work it up to 50mpg at 500 miles, the display is too conservative when compared to pump math. I suppose it's better for the car to report conservative rather than optimistic. I'd hate to do the math and be frustrated!

 

Due to more concern for safety, I try not to worry so much about I-mpg and try to keep my eye on the road. So, I just rely on the meter.

 

Both, actually.

I use display to help me calculate how many more miles I can go before I have to fill up. For a long time I filled up after I'd used 10 gallons (e.g. 480 miles at 48 mpg) because that's when the light went on. Doing that showed me that the display was pretty close to reality-- I'd be putting in just over 10 gallons.

Lately I've realized I can go more than another gallon's worth and still have enough gas to get me to the station, but it is kinda nerve-wracking to drive so long with the light on and no bars left in the gas tank indicator.

I'm working on my own milage database, so I can see how close the readings are to the actual. Should be interesting-- so far I've only entered the first few records... many more to go!

--A

 

I do both. Sometimes the calculations are higher, sometime the display is higher... since there doesn't seem to be a consistant variation, I tend to believe the display.

 

I use the gauge. Math is hard!

I can't even complain that I don't have a calculator handy, since there's one built in to the Nav system.

My driving pattern is too mixed to try to calculate the whole tank. That 36mpg running around town would completely negate the 52 I've managed on the highway. Let's face it: with a 500-mile cruising range, it takes a LONG time to use a whole tank (not that I'm complaining).