I have found the MPH average reading on the computer pretty accurate but not the estimated number of miles left that it is reading. The computer said I had 52 miles left to drive when I filled up and I put 10.84 gal in so at the 28.72 mph I got with that fill up and 4 gallons left, I should have had 114 miles left to drive reading on it. This is the first time I had a car with a computer like this. It that pretty normal to be over half off on the estimate on these computers?