In dash mpg display accurate?
 

Hey everyone, just recently joined the forum but I've been reading alot over the past few weeks.

Anyways, one of my first questions is: How accurate is my MPG display that I have on my Volvo's dash? It has both realtime and cummulative displays. I would think it should be pretty good. I have stock sized wheels/tires on the car so it knows the distance I'm traveling and amount of fuel its using.

If it is accurate, what benefit would I have in purchasing a scanguage?

Thoughts?

with real time MPG's the value to you does go down.That is the main thing I got mine for. It does keep up with the daily, individual and tank mileage;plus max water temps,max rpms,max speed and I'm sure there are some I don't know.I does read codes,but I haven't had need for it.
If my car already had real time mpg, a tach and water temp gauge,I doubt I'd spend the money.Prices do seem to be going down. You may pick up one cheap sometime later.