I'm using a app called "Torque" for my OBD2 reader, how correct is the MPG reading on these things. Its showing around 6MPG more than my on broad computer at all times. To be trusted or not?


Saying that can the cars on broad computer.

 

Don't know about your app accuracy but the best way to cross check both is to fill your tank, zero trip, drive a 100 miles and top up again and calculate your mpg from there....distance travelled divided by fuel used.
This is the most accurate.
I have found the on board computer is pretty accurate when cross checked with this method.