CWS

I locked my cruise control on 70 mph, and reset the "avg mpg" display to 0. Then, it showed 68 mph. It stayed on 68 for a long time. Did it again - set cruise at 66; it showed 64. I know the speedometers are off a little on our cars, but is this other measurement more accurate?

EDIT: Sorry, I meant MPH in the heading and the first line.

jimjaix

iTrader: (1)

I got a noobie question, how do you reset it back to 0?

yov6cam

you cant rest the avg mpg, only tank avg mpg

antb_ball7

iTrader: (1)

WRONG... you can reset the AVG MPG by simply holding down the disp button while its displaying avg mpg...

CWS

^^^exactly. Hold it down for about 2 or 3 seconds, until it changes to 0.

ABC

seems it's usually off by .5 - 1mpg in my car when i compare it to my own calculations.

sirkfc

I think this guy got mpg and mph confused. he means to say that setting the cruise at 70 and resetting the avg speed shows that there's a disparity.

which I think is true, that the speedo is probably fast by a few percent. What that says about our odometer, I don't know.

Fiko18

damn i checked my avg mpg today and it was 16.5. lol that sucks, no wonder i fill up so often

maz

I dont think mine's ever been past 15mpg. Is something wrong. I got about 700 miles on it.

IS_Mine

No you probably do lots of city driving.

The guys and girls here that you see with higher MPG prolly have more I-state driving. I know I do. Finally breaking into 28 mpg.

And my MPH thing is always wrong too. I drive anywhere from 80-90 omw to work and it barely breaks into the 70s.

Bichon

True, but not the only thing that causes better mpg. For those seeing great numbers, it's also likely that a smaller percentage of their driving is short trips, and that they probably don't live in a state that requires a "boutique blend" of winter gas with a high oxygenate content.

Gernby

iTrader: (1)

I agree that he was probably talking about average speed, not MPG.

I'm sure that the Average Speed is as acurate as your odometer. All it does is divide miles driven by time driven. Pretty hard to screw that one up, and checking your odometer on the highway is easy.

CWS

My OP is about MPH, not MPG. If you get up to speed on the freeway while going to work, and THEN reset the MPH to 0, it will calculate your avg MPH more accurately. If you don't reset it, it calculates the avg from when you started the car last, which of course is much lower.

is4fsr

MrMut, that's what I read vs my own calculations. Off by 1/2 - 1 mpg. Does it have something to do with the overall diameter of our tire since we have the 18s" instead of 17"? I wonder if the dealer recalibrated our speedometer when they decided to put 18" wheels.

lobuxracer

iTrader: (2)

The skid control computer generates the speed pulses. There are two different part numbers for the skid control computer. One for standard wheels, and another for 18" wheels. I've already seen this while investigating something completely unrelated.