Instant fuel mileage

[jet]

How close is the instant fuel mileage computer on your truck? (you know the one on the steering wheel controls) Are these things accurate? On a trip today mine said I averaged 27 mpg.

[bigbud450]

My DIC was within .5 mpg of handcalc. Then installed Predator's 65hp setting and DIC said I's getting 24 mpg average on 200mile trip (75 mph run). Handchecked and real mpg was 17. I love how the Predator woke this truck up and a possible 2 mpg increase. Anyone else experience this? :confused:

[Kennedy]

If you use a tuner/chip etc, the DIC reading will definitely be skewed.

The reality is, if you want to check MPG, calculate manually by dividing miles driven by gallons used. Care must be taken to fill to the exact same point each time, and most of a tankfull should be used as the more gallons, the less the margin of error.