SalTex

Just completed a 2000 mile round trip and the GPS went crazy twice. First time was leaving the hotel on second day of trip. Beautiful weather and GPS had been perfect day before but my that day location was off from the start and I finally got tired of it telling me "off mapped road" and turned routing off. Stopped for breakfast after about 30 minutes. GPS was fine when I restarted. Today on last leg of trip we had traveled about 300 miles already and GPS was fine. Stopped for gas it looked okay when we started again but then I realized it was no longer following the road I was on. It showed that I was traveling about 30 degrees left of the direction I was actually going. Didn't really need it so kept going for an hour or so. By then it was off over 60 miles. I was entering town where I wanted it again so stopped for a coffee refill and it worked fine when I restarted the car. So restart so far has worked but no idea what is causing it. I'm driving a 2019 E450.