Re: OBD II MPG Reader
I can highly recommend the Garmin EcoRoute Bluetooth module and a Garmin 1490T. Works great, reports numerous engine parameters in realtime (airflow, temp, timing advance, engine load, etc. etc.), and it does Mileage computations VERY well.
Go to Garmin page, check out EcoRoute. AMAZON was selling the bluetooth module for $69.00 for a while, but I see it's back to $99.00