Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Calculate a correction factor for the odo. Drive a known distance - mileposts on an interstate are usually pretty accurate. Then divide the actual distance by the distance on the odo, and save that number. When figuring mileage, multiply that number by the reading off the odo and use the result as miles traveled.
And for gasoling useage, use the reading off the filling station pump.
Still, I don's see how you could possibly get 3.4 MPG in normal driving. You either have a leak or you're doing your calculations way wrong.