MYO3Z

I found a D3 for really cheap, so I figured i'd give it a try, but I have a few questions after getting it all installed. #1 - Does it take time for the navi to "learn" my speed relative to the map? Because it isn't quite in sync with the streets on the map. i know it might not be perfect, but it's like 4-5 blocks ahead of me after only 1 or 2 blocks of driving. #2 - Why won't my iPod touch (4th gen) charge while connected? Thanks!