When I first got the car, sometimes the GPS seemed to take a long time to load instructions and the map page. I don't know if it has gotten faster or I've gotten used to it. Either way, it doesn't bother me anymore.

However, the other day when I was driving it the map page was just staying blank, and it froze all of my infotainment system. I couldn't even turn off the radio or change the page on the Nav screen. After several minutes, it said that my SD card was corrupt. I turned off the car, pulled the SD card out, blew on it, and put it back in. I haven't had the issue since. I don't know if pulling it out and putting it back in helped or not, but hopefully this was just a fluke, and doesn't happen again.

FYI: The SD card is what the map information is stored on, in the 2013 MKZ.

The GPS in this car is unusually bad. I've had in-car GPS since 1998 and this is the worst of the bunch. It can't figure out where I am, it gets stuck calculating a route, it can't follow me as I drive-- sometimes taking as much as 15 minutes for it to catch up to where I'm at (and I'm not driving that fast). I've been playing a game lately to see if I can get to my destination before it even gives me my first turn instruction. For any trip less than 20 minutes, I generally win!

I've tried turning off all the traffic notices, tried waiting before I move to let it complete its calculation, but in the end, it's just too slow to be useful. I've given up at this point and am now using Google Maps.