Had one that kept trying to lead us down a boat ramp into the Mississippi River.
That same GPS took us on the Blue Ridge Parkway in the middle of the night. I didn't know what I was driving on; I'm from Flat Land(Midwest). But the road just kept turning up, and up, and up... At one point, we were on a landbridge. I didn't know about that until later. My husband just said "do not look off the road"(I am afraid of heights). I didn't. He said it felt like the moon was so close he could touch it...
And then going down...
We were all starting to lose it. Gas was getting low. We worried for the breaks as you say, and at some point my husband started panicking and saying the car was going to break down and the Mountain People were going to eat us. My eyes are not good, and there were no lights along the road, but strangely, at the point I thought I couldn't drive anymore, this giant purple 'light blob' lit up my way and I got down just fine. It didn't seem odd at the time, but I just focused on it and went down the mountain. I didn't think about it again until later.
I don't really care what it was. Godform, mountain spirit, angel, or hallucination. Makes no difference to me. I was just thankful!