My 340 getting 6 mpg

Is your speedo accurate? Is it possible that your actual miles driven is not correct? Just
Speedo no worky. I think he's using the navigation mileage and fills the tank deduced by how much he can put in the tank bringing it to full again.
Speedo not working doesnt mean anything. Im getting bad MPG bottom line ! Lol
Is your speedo accurate? Is it possible that your actual miles driven is not correct? Just a thought.
Speedo not working means nothing lol. I know the miles om traveling. Are you fuys serious ??