Happy Monday Guys and Gals,

So this weekend I made a trip from Harford County to DC to see my mom. Which is approximately 80 miles one way. So I switch the computer to the "cons" screen and it moves constantly when I drive. But when I switch to the "avg cons" screen it says about 29.1. How the heck do I tell how many miles I am getting per gallon? FYI I was driving between 75-80 in a 55.

Also if I did not break the car in by the book would any gas mileage shortages occur?

Thanks folks.

 

• Fill the gas tank and reset trip computer.
• drive until you need gas again
• record how many gallons you put into the tank.
• Divide the total miles you drove by the number of gallons you put into your tank.

That's a reliable way to calculate it. The OBC is way to optomistic to be relied on.

 

29.1 is the average miles per gallon your getting since the last time you reset the computer (held in the button wile on Avg Cons) The 'cons' screen shows your fuel milage for right then and there. Soooo.....with that said, your fuel milage right now is 29.1 MPG

 

Pssst - best not to talk about driving significantly over the speed limit, or I'll be ib4tl.

As for your question, 'cons' is the estimate of 'instant MPG', what you're getting at that point in time. 'avg cons' is the average of your MPG. You'd need to reset it before a trip to get the MPG for that particular trip. Note that my OBC generally overestimates my MPG by 11%.

 

Only problem with that is, when was the last time you refilled after running completly out of gas? Doing it that way requires that you calculate at the excat point that you refilled from.

 

So is it a good assumption to believe that I am getting 34 mpg, and that the break in period does not determine the mpg for the car over its lifetime?

 

Umm... If you do it like he said, refill (all the way up) and then reset the trip odometer, than the next time you fill it all the way up again, than the amount of gas you used should line up with how much you put in the tank, and than you divide by the number on the trip odometer you should have your MPG. As long as you reset the trip odometer everytime you fill up than it will always work no matter how much you put in as long as you fill up every both times.

 

im dyslecic (not really) i read step 3 and 2 reversed :( my bad.

 

I've found the OBC to be optimistic when it comes to computing mileage. Like Dave said, do it by hand. You can easily use your mobile phone or keep a $1 calculator in the car.