I just bought a 2005 Jetta about 10 days ago. I'm 22 and I just sold my very first car ever to trade up to my new Jetta. I love it, but its new to me and it has every bell and whistle and I'm still figuring out how to navigate the dash. Here is my question:

The entire time I've had it, the in-dash display shows my MPG. It is almost always 23.9-24.1, and it stays fairly constant. I just hopped in for a ride a few minutes ago, and the MPG meter now changes wildly from 0.1 mpg-90.0 mpg. As far as I know, I haven't messed with any of the settings. I'm wondering if I'm just being ridiculous or if there might be a problem with the computer?

Thanks

 

You can try resetting the ecu by disconnecting the battery cables and holding them together for a couple of minutes. If that doesn't do it I would think it would be the ecu unless there is a separate device that controls that somehow.