gdw0717

I tried something the other day that makes me question how accurate the on-board gas mileage computer really is.

Try this, with the engine running but sitting in park/neutral reset the mileage computer. After several minutes mine continued to report 2-3 miles/gallon.

Should it not report "0" mpg at an extended period of time with no movement? If the computer doesn't have a value for speed the math should return "O".

2-3 mpg at a standstill would explain why I get about 2-3 mpg below what the computer says when I do the math.

Is Jeep hoping no one would notice and figure they are getting better mileage than they really are? I would be interested to see what others get when they try this test.

derff96963

I will give that a try but with reseting mine every fill up I am usually within .5 MPG of what the dash tells me. To me thats plenty accurate enough.

HULKGREEN

Most find the dash to be off approximately 1.5 to 2.0 mpg......

When you sit still and idle ...the computer is averageing in the 0 miles to the gallon with your other averages...... so I trick it and turn off the engine instead of sit with it runnin !!

derff96963

I have found if you sit and idle and keep reseting it you can get 0. The problem is when you reset it it clears the mileage but it keeps the current mileage to average in to what it was before it was reset.

For example if you had 18MPG and you reset it, it will immediately say 18MPG and if idling quickly fall. However its averaging the 18 in so it won't hit zero without more resets.

Now mine like I said is usually only .5 or so mph off of what I calculate. That's plenty good for me.

jeepcanoe

20 mpg 4door 6sp with 3.21 rears