Reset Nav location

Over the 4th of July I took a car ferry trip from Milwalkee Wi, to Muskegon Mi. While in the hold the car could not get a GPS signal. When I arrived in Muskegon for a few minutes it still thought I was in Milwalkee. Then it knew I was in Muskegon, but was still not exactly right. After a few more minutes it found itself ALMOST. Since I've been off by a city block. I went and used the tool that will let you tweak where the car is. After playing with that I F'ed it up and it is way off now. At least a block. Every tweak I make now it makes it worse. With the Nav it will snap to which street it thinks it is on, not to it's actual location.

Is there a way to have the Nav un-snap from the location it thinks it is?

What I did was drive to an intersection, say pointing north, and stop right on the corner. The map would show I was off by a bit. So I had it move my position to the corner. Then I'd head East and stop at the corner and move it to the proper position. Sometimes now I'll be in the middle of block, then it will snap to the nearest street.

Please help.