So I get my D3 and put it into my car after taking it out of my friends car. Same type of car and everything. I notice that on the map the arrow is pointed straight up or at some weird angle with the map moving behind. The arrow is moving sideways on the map. I've tried switching the setting to true north and back. Done everything I can think of. Resetting the unit with the little reset button next to the eject button. Can anyone think of something to try before I pack it up and send it back to Pioneer?

Clear the unit's learning status? Even tough they may be the same vehicle, it might be sending slightly different info to the unit.

Weird. So tapping the compass doesn't fix it?

Give it some time to finish its learning sequence. You can also adjust your position/direction manually.